In the early 2000s, it was not terribly uncommon to meet a punk kid with a soft spot for the Mates of State. Though I'm sure the word "joycore" was often stammered in justification, it actually made a lot of sense: There was an unmistakable DIY spirit to the band's earliest material. Husband-and-wife duo Jason Hammel and Kori Gardner's voices joined in imperfect, occasionally overripe harmony, and their songs were patchwork pieces with seams proudly showing ("We attach parts together until they make a whole song," they once confessed)-- all of which added to their debut record's unique and infectious charm. Unlike much of the impersonal, digitized pop that was emanating from the radio waves or your little sister's primitive, brick-sized mp3 player at the time, My Solo Project was pop music that felt transparently and exhilaratingly human.

A decade later, certain core facts remain: Kori Gardner and Jason Hammel are still happily married, they are still an organ-and-drums two-piece, and you'd still convulse in a fit of sugar shakes if you found a way to bite into one of their songs. But a funny thing happened somewhere between 2003's rollicking Team Boo and the AM-gold glimmer of 2006's Bring It Back: Gardner and Hammel became pretty great pop songwriters. Their harmonies got more technically sound, their songs moved more fluidly-- basically, the seams don't show anymore. Bring It Back proved that this wasn't necessarily a development for the worse. But the band's last effort, 2008's Re-Arrange Us, was a misstep, not just for the much-cited reason that Gardner traded in her electric organ for a bland-sounding piano, but because the record's overall energy was inert. And if the damn Mates of State can't muster the energy to sound enthusiastic about anything, heaven help the rest of us.

Mountaintops brings on an immediate sigh of relief: Its opening minutes are not just a return to form, but one of the most zinging 1-2 punches in the band's catalogue to date. "Palomino" is celestial pop with a chorus as big as the sky, and the warped synth groove of "Maracas" is irresistibly catchy. Suffice to say that if you don't get "Maracas", you don't really get this band, because it manages to cram almost every single reason the Mates are such a perennially charming guilty pleasure into a single song: holler-along lyrics that don't make a lick of sense ("Wooo-oooh/ Syncopated breathing!"), posi-energy to burn, and even a totally gratuitous Queen Latifah reference for good measure ("I've got your back/ U-N-I-T-Y!"). But if you can see past its feel-good vibe, "Maracas" also hints at the record's overall thematic maturity.

Some more core facts about the Mates of State: Gardner and Hammel quit their day jobs 10 years ago (teacher and a medical researcher, respectively), they have spent the past decade in the record-tour-record state of eternal return, and they have been raising two children all the while. Mountaintops is the first of their records to grapple with the everyday tribulations and banality of spending your entire adult life in a band-- with your Mate, nonetheless. "Basement Money" is a surprisingly honest exploration of something few indie bands are brave enough to sing about: the necessity of making money off your art. "At Least I Have You" pulls the veil back even further. It's a song not just about feeling disconnected from old friends and familiar places, but the realization that the music you've devoted your life to playing is the only thing that can bring you release.

Much has been made of the Mates' cheerful music as a testament to how completely and adorably in love they are, but Mountaintops intrepidly explores themes of isolation, codependence, and the things lost from operating for years with-- to quote "Basement Money"-- "a doublemind." The chords that play out final track "Mistakes" are bittersweet, and there's something unsettling about the lingering last words of its refrain: "I need you/ But it's not normal if I refuse to be by myself."

Mountaintops is not without valleys: the breathy balladry of "Unless I'm Led" is a bit too maudlin even for the Mates, and the Motown-meets-glee-club sugar rush of "Total Serendipity" is divisive at best. But overall, Mountaintops finds the Mates taking the more nuanced emotional tenor of Re-Arrange Us and splaying it across the mural-sized pop canvases we've come to expect from them. Impervious to trends and refreshingly uncool, Mates of State have managed to progress and mature within the confines of their own self-made niche. All of which is pretty punk, when you get right down to it.