Have you noticed a difference in handling of VBRs in your DJ software? I use Mixxx, and that's not been something I've noticed. Someone I regularly have tag-team DJed with uses VirtualDJ and he never complained about me sharing VBR files with him.
I have noticed that older pre-2.0 versions of Mixxx would sometimes get glitchy (warbly) when using the pitch-correction feature (key lock, I think is the name in the UI), but, I don't think it's related to VBR vs CBR, but I never thought to check.
The only time I've noticed an audible sound quality problem when DJing was with low bit rate (usually 128kbps) files.
Mixxx developer here -- can confirm our VBR decoding code is slightly less reliable than CBR! It's easier when you know exactly how many samples you're going to get out of a frame. We rewrote a bunch of this in 2.1 (coming in Q1 2016) so hopefully a few odd VBR quirks we had got fixed.
The warbling definitely sounds like our pre-2.0 time stretching algorithm to me. The new one in 2.0 is much better.
I love Mixxx! 2.0 beta is really fantastic. And, it's enough better and more reliable than 1.11 that I'm confused why y'all haven't done a stable release from that branch (but, it's good to hear it's coming). I haven't noticed the warbling since upgrading to the beta, I don't think, and a number of other big annoyances and crashers have also gone away. The additional capabilities (I upgraded specifically to be able to use the mic/mixer inputs on my controller, which 1.11 can't do, at all) and the nicer scratching and such is just great. In short: I see you've got a call out for testers of the RC; but, honestly, I already believe 2.0 in versions from months ago are more reliable and capable than 1.11. Anything that delays a release of 2.0 is just leaving lower quality software in the wild for longer than necessary.
Anyway, I really appreciate your work on Mixxx. I don't get to do audio or music work much these days, but I do occasional DJ gigs (mostly for free for non-profit orgs and such, but sometimes they're paying gigs), and it's been a whole lot of fun.
Glad you like it :). We're working on the last mile stuff right now (updating the manual, website, etc.) -- it will definitely be out before new years!
Not specifically. I play around with Mixxx but use Traktor in the club. It's more about software stability than anything inherent in the sound. I've had a handful of sets go south (which ultimately is enough) due to freezes etc that I'm wary (unnecessarily so. I'm sure they are fine, but It's more about "simplifying variables in arguable a super complex system.)
I have noticed that older pre-2.0 versions of Mixxx would sometimes get glitchy (warbly) when using the pitch-correction feature (key lock, I think is the name in the UI), but, I don't think it's related to VBR vs CBR, but I never thought to check.
The only time I've noticed an audible sound quality problem when DJing was with low bit rate (usually 128kbps) files.