I have no parrotlet experience, they've always seemed pretty similar to me though. I've even heard both called "mini-amazons" for their temperament (which is only true for parrotlets, lovebirds are from a different continent.)
I hear male(?) parrotlets are more likely to talk, neither gender of lovebirds are really known for talking. Could be wrong on the parrotlets; again, no experience.
I would describe Peanut as both comical and feisty too, I don't know that a parrotlet would be more so.
One thing I do want to add is that thing about them going wild quickly is a myth, or at least widely misinterpreted. I'm sure they do become less tame if they go extremely long periods without being handled but I've not experienced any of that with Peanut. I've gone out of state for two weeks and occasionally take 1 week trips (not often these days.) Once several years ago she was so hormonal and grumpy she didn't want to leave her cage for about a month. Once I get back or she settled down there is little indication she is less tame. Sometimes she will bite first thing when I ask her to step up (like "how dare you leave for that long!") but then once she has made her opinion clear she settles down. Then is generally very happy to see me.
I wouldn't get either bird (at least singly) if you don't intend to interact with them most every day anyway, so it shouldn't be an issue.
If I had to choose, and assuming the impression I have about both species is correct, I would choose lovebirds just on the basis of them being slightly larger (and, to be completely shallow, slightly more cute IMO.)
Size makes any veterinary care they may need a tiny bit easier; there isn't a lot of room for error in
any of the little species but being 15 to 30 grams heavier is just going to make things like anesthesia or being medicated a little bit simpler in the hands of a skilled avian vet.
That said, even a large lovebird hen at 65 grams will never be a good candidate for surgery and anesthesia is risky for most birds. I don't know how much greater the risk really is in a 35 gram bird versus a 50 gram bird. Just the smaller the animal is, the harder and less safe it is (in my understanding.)