I own the Quad 21Ls.
I would not call them "pronounced" I would call them non-forgiving. If you feed them a bright etchy source, that's how they will sound. Not saying that's the case with your Rotels, but that certainly was the case with my setup before I fixed it (almost done fixing but not quite). I've tried them with 6 different CD players, a few different amps, and a bunch of different interconnects and each time the Quads were resolving enough to differentiate between each of these changes. They will show you what you have upstream, so be prepared for it.
Regarding 11 vs 12 vs 21.
I think the 11L probably has the best midrange of the bunch, but for me low end extension was important. So I was looking at the 12Ls. 12Ls + Stands was just a hair less than the 21Ls, and the 21Ls have lower response than the 12Ls. So I went for the 21s. I'm very very happy with my speakers, and find the sonic characteristics of the 21ls to be very similar to the 12ls, except with more bass.
If you have any questions please feel free to e-mail me!
A description of the process in deciding between the various Quads is under my system, and in my past threads you can see the various sources I've had in my system when I did an inhouse roundup of Rega Planet 2000, Roksan Kandy mkIII, Creek CD50mki, Cary 308, Arcam 73t, Cambridge Audio Azur 640c.