Flo Rida and Jennifer Lopez are both the universal donors and universal recipients of pop; they'll collaborate with anybody. So it makes sense that "Sweet Spot" isn't their first teamup. What makes zero sense, though, is that the track where Flo Rida takes lead and J. Lo takes featured vocals would be better than the track with J. Lo on lead, but, well, here we are; "Sweet Spot" is a million times better than "I'm Goin' In."
Let's deal with Flo Rida's part first, because it'll be quick; it's identical to Flo Rida's part in everything else. It's rumored that if you amble down any street in Miami, stand very still and listen very closely, you'll hear the exact backing track from this. (Then Pitbull will materialize in a spritz of sponsored vodka and do a verse over it.) The only thing noteworthy is that he says "watch the throne."
J. Lo's part, however, is something else entirely. It's a gauzy coo, plaintive and even delicate; the backing track could even be called twee. The closest analogue in mainstream pop's probably Fergie on "Clumsy" or "Just Can't Get Enough," but purely on sound, a better comparison might be Cassie or Alison Goldfrapp or Jess Mills. This sort of vocal is fairly easy to do, of course, and to find elsewhere; it's not a bad idea when J. Lo's not singing about much in particular (summary: candy is sweet and desirable, much like sex, and don't think too hard about that metaphor with this vocal mode.) But it's undeniably pretty. At the very least, it deserves to shut up everyone who says Lopez's voice is bland.
Is "Sweet Spot" a good track? No, not really--the two parts don't fit together at all, making this completely incoherent even by 2012 pop standards. Is it interesting, though? Sure; it's probably the most interesting thing
Flo Rida's ever done. That doesn't say a lot, but it says something.