I've paddled both on flatwater for about 10 min each, so my experience is limited with these (I normally paddle a millenium and Mako6). Stability is roughly the same for the two. I remember the rookie having a very smooth transition from primary to secondary stability - seamless - which isn't necessarily good nor bad. The Evo stability is smooth but you can feel it firm up as it rolls to the side. Both are roughly the same in stability and solidly between the V10/race Fenns, and the entry skis like the XT, Sport, and the S1R. My speculation based on what they looked like and felt like on the flats, is that the Evo would be nicer and faster in milder conditions but the Rookie would be nicer in big stuff like Molokai due to the extra volume, rocker.
