I've said a few times on other threads: when it came out in spring 1977, I absolutely HATED "Love You." But I gave it a chance and kept listening, and now it's one of my five favorite BB albums.
I'd say the question shouldn't be "why do you now like it" but rather, "why DIDN'T you like it before?"
For me, it was a combination of the following:
* On its surface, it sounded like nothing the group had done before. It was certainly a radical departure from the commercial, accessible FIFTEEN BIG ONES.
* The group's hoarse vocals and the somewhat thin (in spots) background vocals were jarring to someone who was concurrently discovering the group's "classic" records, which, vocally, were ANYTHING but "thin" or "weak" or "hoarse."
* Some of the lyrics made me cringe.
* Like the vocal sound, the synth-based instrumental settings were jarring.
That was what I DIDN'T like about LOVE YOU when I first heard it. But I think it's an amazing record. It takes risks, for one thing (like I said, no BB album before or since was such a radical departure from what came before in so many ways).
Musically, I think the arrangements are stunning: the voicings and the way the different instrumental voices play off of and almost "talk to" each other (best example: "I'll Bet He's Nice"); the drum parts (one of the best examples ever of how Brian couldn't be satisfied with a drummer who pounded away on two and four, but who played patterns that, again, played off and "talked to" the other percussion and instrumental voices). The use of the group's individual lead voices (again, exemplified on "I'll Bet He's Nice," where Brian has his brothers trading off the lead vocal part almost line by line). The BACKGROUND vocals, which, am I the only person who has noticed this, was the last time that the group had a new album dominated by their classic background vocal blend of Mike on bass, Carl, Al and Denny in the middle, and Brian high and sweet in top...and speaking of "Brian high and sweet on top," SCREW that awful, awful, hideous AWFUL TRACK "She's Got Rhythm" on MIU that everyone oohed and ahhhed over ("Brian's singing high again!" Yeah, but THE SONG SUCKS!!!)...Brian's falsetto lead passages on "Airplane" are not only among the prettiest singing he ever dud; they're also pretty much the last time that he sang like "the old Brian."
The sweet dumbness of the lyrics, which, the more I listened, fit the melodies and the tone of the songs and sounded just fine to me if I didn't THINK about them too much.
And the cover. I liked the cover.
And the title. In angry "rock vs. Disco" 1977, when the last best hope for rock and roll seemed to be angry new wave or angrier punk, the title THE BEACH BOYS LOVE YOU was a breath of fresh air. The Beach Boys love ME? Why, thank you!

It's just a sweet, complex, weird, quirky, beautiful album that works on so many different levels that it's easy to dismiss it...believe me, because when it came out, I dismissed it. But to me, LOVE YOU stands right there with PET SOUNDS in terms of multi-leveled sophistication, which is why the more you listen, the better it sounds... there's a lot there to hear, and the more you listen, the more you notice.
That's my take, anyway.