the main benefit of XL is digital audio extraction with cue sheet support. if you aren't concerned with that or use another program (e.g. EAC) the PT Pro 2.XX is sufficient.
supposedly, XL is built from scratch as opposed to being based on PT Pro but there's been no evidence that the burning engine and/or Q-Check features perform differently. rumor has it they're adding a new feature to the next version of XL but ATM it's not worth the added cost.
btw, welcome to the CDFreaks forums