I've owned a few L2's and XL2's. Curious to see if others who have owned both had a preference in one model over the other in the areas of, 1- tone, 2- feel, 3- hardware/setup.
I currently am using my L2, but miss my XL2.
I have one of each--an early "transition" XL2A (it retains the curved detachable leg rest and SS pickups from the L series) and an L2UF (unlined fretless). Both are from 1984.
I love them both. They are different, however. The L must be at least a pound lighter and the neck both feels more hollow and is a bit thicker, front to back. I would say that the XL is definitely a little nicer, fit and finish-wise. You can easily see where the fingerboard attaches to the neck on the L, for instance, whereas you can't on the XL.
I can't compare the sound very precisely since I keep flats on the L, but I'd say they're quite similar. The only claims I've ever heard regarding a difference in sound centers primarily on the pickups. Early in the production of the XL series they modified the pickups (from SS to HB designation) which according to many rendered them a bit less warm in tone. I can't vouch for that personally since both of my basses have the earlier SS design. EMG however now makes an HBCS model that replicates the features of the SS so there must be at least something to the idea.
I have read on many occasions that the bridges on the L series were produced in-house out of milled steel while those on the the later XL series were some kind of molded zinc and were produced by an outside supplier. That might make some small difference in the quality of the sound, I guess. I have heard that they are not as durable.
The L series were more expensive on the used market for a long time, but I notice that difference less these days. I think it was mostly driven by collectors (who presume, because it's true of vintage Fenders, that older models are more rare and better) and not by player preference, though. It might also have reflected the fact that most of the really famous players that took them up for a while (Sting, Geddy Lee, etc.) played L series instruments. That was the only available model when they played them, however, so it couldn't reflect any particular preference by them.