There's a conundrum faced by certain bands, successful indie-rock ones especially. If the first album or two have broken through and lifted the band above the horde of contenders, should the band continue operating on their current level, which has brought them this success, or should they use the success to try to reach the next rung on the show-business ladder? Record company or management pressures aside, what does the band want to do?

The Shins and Clap Your Hands Say Yeah, both out of the US, are in this position. The Shins are a four-piece from Portland, Oregon, though they started life in the less-fashionable state of New Mexico. Wincing the Night Away is their third album, and they're on the perennially hip Sub Pop label, out of Seattle. So it's a West Coast operation, which immediately separates the band from Clap Your Hands Say Yeah, who are from the East Coast (Brooklyn and Philadelphia), are on their second album - Some Loud Thunder - and have their own label. The bands play different kinds of music, too, which also neatly reflects the coastal divide. The Shins are a pop band: curling melodies, a radio-friendly lead voice and not-too-disconcerting lyrics about the boy-girl situation. Clap Your Hands are pure New York City, the latest in a long line of bands that worship in the temple of The Velvet Underground. Both bands have successful albums behind them, and both have reached the same conclusion: get the producer.

For Clap Your Hands, the decision is more surprising. Given the sonic range of their music and its roots, they could have stayed in town and made an album like their last. They haven't gone too far, though: along the road to Dave Fridmann's studio, in upstate New York. For some time, Fridmann has been an in-demand producer for adventurous bands with a budget. The Flaming Lips, Mogwai and Sleater-Kinney have all used him. His masterpiece remains Mercury Rev's Deserter's Songs, one of the very few great rock albums made in the last ten years. As a choice of producer, it's understandable, not too predictable, and definitely a step up.

The Shins have also looked in their backyard, although LA is some way from Portland, and come up with Joe Chiccarelli, an adaptable pop craftsman. The record company mentions Beck and U2 as his clients, but skips Elton John, Bon Jovi and Chicago. No matter; he would've been chosen for a certain expertise that he could bring to the album, something the band wanted.

The Shins' rise has been measured but steep. Their debut album, Oh, Inverted World, came out in 2001; Chutes Too Narrow, the follow-up, was released in 2003; and now, four years later, comes their third. Chutes was always going to be a hard act to follow. It's a very good album: ten beautifully arranged pop songs based primarily around the acoustic guitar. Its success, though, seemed to have more to do with an aura floating around the record - the singular vision of James Mercer, the band's singer-songwriter, who, with his boyish angelic voice, built a world through his songs that people rushed to inhabit. It was hushed and intimate, like diary entries, but backed by solid, real-world pop smarts. The album broke them out of any small market that they had in mind, and set them up for a shot at the mainstream - if they wanted it.

The gap between recordings has allowed the band time to make their decision and prepare for the assault. The results are radical. Gone is the classic indie production of Chutes; in its place is the smooth, thick, synthetic sound of major-label pop. The twist in this - the out-card, if you like, for the band - is the record's loving embrace of the '80s. It's as if Mercer and co.'s jump to the mainstream can be facilitated, encouraged even, by a warm clasping of The Smiths (very noticeably here), U2, some Cure, and early Crowded House. The production decisions and the sound go hand in hand with this, which helps explain the old-school choice of Chiccarelli. For fans, it's a shock; for the new audience, the welcome mat is particularly shiny.

And what of the songs? They're strong; the ones on Chutes pip them, but Mercer is too good a songwriter to let his side of the bargain down. The more important matter is what the sound does to the songs. The first and most obvious thing is that Mercer has been pulled back into the band, both in his vocals and in his presence. His voice has lost its adolescent tremble and he now sounds more like The Cure's Robert Smith, detached and lower in the mix. At the same time, the drums have come up and acquired a noticeable '80s-style whack. The electric guitar has all but overtaken the acoustic, and has a distinct Johnny Marr ring to it, right down to the tremolo touches and snaky minor-seventh flourishes.

The effect is a distinct coldness. The band sounds removed; the collar-grabbing freshness has been replaced by ambient pop. And for the most part, it works. Chutes, for all its brilliance, had them in a corner, and trying to remake or fake its naivety would have been fatal. So they've set out for a new sound, one that weds the next phase of their musical development to their commercial aspirations.

Over on the East Coast, it's a different story. For Clap Your Hands Say Yeah, commercial considerations are not so important as establishing a career as a credible, close-to-the-edge rock band. The way to do this is to stay the course, making well-judged adjustments to their sound (hence David Fridmann) while banking on their songwriter to consistently produce quality material. It's what worked on their debut album, where one good track galloped into another; it's the lack of a steady flow of strong songs that lets Some Loud Thunder down.

The five good ones on the record are those that are more poppy and melodic: these the band's singer-songwriter, Alec Ounsworth, can write and write well. It's the other sort of song that's the problem. He has various stabs at constructing things that might break up or angle off from his strengths, but none of them is good enough. More worryingly, most have a pretentious, getting-clever-in-the-home-studio feel to them, which acts as a further turn-off. ‘Satan Can't Dance' is a flat ‘funky' anti-dance song; ‘Arms and Hammer' tries too hard to be a strange folk tale; ‘Love Song No. 7', with Ounsworth's voice multi-tracked, sounds like Supertramp. Only ‘Upon Encountering the Crippled Elephant' (it's weird-song-title au go-go with these guys), a short and pretty waltzing instrumental, manages to construct something that links the fine pop songs together. And the fine pop songs really are marvellous, twisting, inventive takes on post-Velvets rock.

A barrier to the band, all but ruling out broader success, is Ounsworth's voice. It comes in two broad guises: Gordon Gano of the Violent Femmes, and David Byrne; the shadings are Television's Tom Verlaine and Dylan circa '64, the ‘It Ain't Me, Babe' era. It's not often that you can characterise a singer by naming so few influences, but Ounsworth swaps so freely between his inspirations that it almost creates a vocal style in itself. He also uses them on songs that recall the bands whose singers he sounds like. So the quicker-strummed, wound-up numbers have the nasal whine of Gano, while the more laid-back numbers - or the quieter sections of songs - have the Byrne croon. The similarities with the latter are so close that ‘Over and Over (Lost and Found)', on their first album, sounds like the great lost late-'70s Talking Heads song. And being a Talking Heads obsessive, I found it was this number that first drew me to Clap Your Hands. Its simple two-chord elegance and uncluttered post-punk approach are missed on much of what they've done since.

Neither of these albums is a complete success. The Shins have lost too much sparkle; Clap Your Hands are in the studio too early, and haven't managed to reach that desperately needed next stage. So, two of the more significant indie hopes for early 2007 fall short. Of course, market forces may take over for The Shins, who are a pop band and have certainly made a pop record. But Arcade Fire, Kings of Leon, Art Of Fighting and other big shooters are on the horizon, with records coming soon. Salvation may lie there.