Sandra, I agree it's not intuitively obvious but the tracks do sound better to me at least. Now, as to your comment about stretched files vs original files I don't think that's what the comparison is with this. I believe there is only one original RT file per any given tempo. Those other +/- files were already stretched and included with your original RT's to help with different tempo's. It's those previously stretched files that you no longer need because the new stretching system does it much better. If you want to test your ears, compare a RT track in Biab at the exact original tempo of that track and then do one 10 or 15 beats faster or slower. That will use a previously stretched track using the old method. If you don't hear any difference then the worst is you won't hear any difference now using the new method but most of us hear an improvement. Then of course there's the vastly improved amount of tempo stretch you can get now. I've done some changing up or down 50 or 60 beats and they sound great.
There's also been comments about the generation times, my machine is getting a bit old, P4 2.8, 2 gigs ram, XP SP3. Some say it's a bit slower but it's actually a bit faster on my machine. Who knows why, just different setups I guess.

Bob

Biab/RB latest build, Win 11 Pro, Ryzen 5 5600 G, 512 Gig SSD, 16 Gigs Ram, Steinberg UR22 MkII, Roland Sonic Cell, Kurzweil PC3, Hammond SK1, Korg PA3XPro, Garritan JABB, Hypercanvas, Sampletank 3, more.