ive had my 2500 w jj1 for over 3 yrs, got an xl w/8 outs, fx n memory about 2 yrs ago coz it was local and wanted to experience the limitations etc.. used it for over a yr then moved back. coz it freezed on me a few times when it was hot and i got too quick for it, when switchin modes too fast. on the 2500 thats not a problem, it just hangs for a bit sometimes.. im fairly quick with the xl and a master on the 2500. it gives me way more room to be lazy with the memory, and copy programs etc.
only 4 programs at a time on the xl is pretty limiting for me.. is there any way to use more?

the xl did have a certain bright color to it and emphasis some low mid and some mid hi frequencys. where as the 2500 is flat i guess. the resonance is alot better on the xl and that is the biggest diference soundwise for me, the lpf has a warmer sound on the xl too imo. the 2500's filters are pretty good and you can shape the sounds way easier w/two filters. using the xl was a bit more fun, finding zero crossings was much easier on the xl, rounds the sound a bit more.. i can get a smoother sub bass sound from my 2500 with the two filters but still needs a good tweak.. i thought the xl's fx-filter sounded great and was alot better than 2500.
loading the waveform in trim is really slow in comparison but while timestretch is really slow it is much better than the 2500. the 2500 timestretch can get really grainy and might have to retry 10+ times to get it tight on the xl was good most the time and sounded better.
they can both get dirty, i don't think that's the issue.. it's what you put in and knowing how to get that sound. they both don't sound amazing from scratch, you have to tweak both in some way to punch the sound out imo..
unlike my korg esx which i had a a yr before i got my 2500, just turning up the tube gain was bad ass. i still have all machines, this makes me want to fire up the xl and get busy.
i switched back to the 2500 bcoz of the much faster workflow, +1 on input thru being one of the best features compared. i might dust off the xl before i decide to sell it.. it's mint fully maxed w/card reader i installed. i bought it for $1400

before the card reader a bit over 2 yrs ago. i doubt i'll get that back, lol!
happy i got it though, much different workflow, both fun.. 2500 is a beast! hd is a big plus!