Hey, I have the RC 2 and a Digitech Jamman and used to have the XL. Hands down, the RC2 is the choice due to the drum backings on it, the XL doesnt have much usable drum backing, theyre midi.
The Digitech however lets you record upto 6 hours and 99 patches are a must for recording everything. Once you start saving your patches on the Boss pedals you be disappointed you can only save 11 of them. And the Jamman also lets you save to PC and has a Midi input plus a couple other extras. Now that Ive had all three Id say this, The Boss RC 2 if I could only have one, its better at accurate recording and dont see any advantage to the XL over it other then reverse which is cool but taking away the great drum clips isnt worth it and RC2 is cheaper. In the end, the Jamman is great for having all that storage but just isnt as solid as the BOSS over all, I'd still recommend it as a home fun unit. Let me know if you have any specific questions on any of them.