Way back in 2000 (that phrase seems so wrong), the debut disc from Mates of State, My Solo Project, was much lauded for its gleeful, rough-around-the-edges take on indie pop. The married duo of Kori Gardner and Jason Hammel propelled themselves forward on rabbit-thump drumming, gleaming keyboards, arching vocal harmonies, and, probably, a pretty decent amount of sugar. Their pop hooks were readily apparent, but there was a charming messiness about the thing, a sincerity that shone through in the fact that this wasn’t lo-fi for effect, that these were two musicians finding their own place, their own sound, and their own potential. Since then, their stock has considerably risen, and with each successive album, those rough edges have been sanded down, little by little. But rather than losing any authenticity, the duo have kept their strengths, all while bolstering their sound with new instrumental flourishes and stronger songwriting to couch those still-powerful hooks in.

To be sure, though, 2008′s Re-Arrange Us did have its missteps (it sounded, somehow, as if that raw, excitable energy had been subdued), but it was still a relatively solid indie pop record. Gardner’s switch to piano from her usual electric organ caught a lot of guff, but, in the end, the songwriting on the album was another step in the right direction, and the addition of bass and cello was an ingenuous use of the studio to flesh out their material. So, in many ways, their new disc, Mountaintops, could be seen as another test of their progress, whether they’ll move further along or catch on the new developments they discovered last time around.

From the opening twinkles of “Palomino”, though, it’s clear that the pair haven’t delved further down the Re-Arrange Us rabbit hole, instead delivering a return to the heavy handfuls of happy chorus that they’d done so well. The skyward soaring, wild, wordless vocal flourish that permeates the track, along with lines about “touching in the backyards of our youth” and how “I’ll never leave you” are pure adrenaline smile-inducers, and the song’s cresting wave structure, complete with wobbly breakdown and stunning pounded drum recovery, is another example of how far they’ve come as writers.

“Maracas” follows, its wonky organ riffs slippery and adorable in a Yo Gabba Gabba sort of way. But when Gardner’s multi-tracked vocals pitch in, the song gains a funky edge, particularly along her upward trilling chorus. Despite the song’s back-and-forth talk about not quite knowing someone the way she’d thought, the closing lines of “I got your back/syncopated breathing” is one of the more deftly straightforward statements of a relationship’s power in recent memory. While it plays into all of the issues that Mates of State haters have (massively joyful, big, indulgent vocal harmonies and cutesy instrumentation), it’s a great song, both lyrically and musically, and should readily please any non-Grinch.

The bombastic, ’80s cartoon nostalgia intro to “Sway” rings out a little too dramatically, Gardner belting out a yelped “oh” a la Zola Jesus. But no matter how cheesy it may be, the married couple harmony of “please sway with me” just sounds so sincere. Even at their musically least interesting (which this song is), the duo’s sincere delivery saves it from being another cheesy nostalgia track. The tom-heavy drums and plinking strings on “Unless I’m Led” are an interesting change of pace, vaguely Andrew Bird-y in tone, while Gardner’s lithe ballad delivery is fluidly framed by Hammel’s more staccato backing. This one-ups the dramatic quotient as well, but really, that’s what Mates of State do best. And exactly to that end, “Total Serendipity” follows immediately after, the piano-driven, Motown-y stomp rushing forward like something out of a cut Grease sock hop scene, at least until it slows itself down, at which time the repeated lines “You’re a pot of gold sitting at a rainbow’s edge/There’s a marigold growing in between your toes” are almost too twee to be true.

The talk of “what a double-mind can do” and the hard work of making music on “Basement Money” could all too easily be read as autobiographical. The repeated chorus of “We wait/We don’t give up” is uplifting enough to fit in with everything else, to be sure, and the talk of selling out and needing to “make a living somehow” concurrent with a love of music is pretty honest-sounding. The snappy rhythm and spotlight synths keep this from being an apology for their success. “At Least I Have You” similarly focuses on what could be taken as real, a story of music and touring replacing lost friendships. The fact remains, adorably, even through the dark, retro synth push, that the two have each other. If that sentiment sounds over-the-top, then Mates of State aren’t a band for you. If instead you’re giggling and aww-ing, then this is right up your alley.

That distinction has been one that runs through Mates of State’s discography, and it’s certainly one that the success of this new disc depends on. As their audience expands and their reach grows larger, it would seem that the cute is welcomed with open arms. Take that undeniably delightful charm, add their increasingly laudable songwriting, and pepper in some wise instrumentation choices, and this makes for a strong album, one that bodes well for more in the future.

Essential Tracks: “Palomino” and “Maracas”