I picked up a used Villain S in the latter half of last summer and I really like it. It didn't feel too sluggish to me, but I was coming from a Hero, so it's hard to say. However, unless you're doing a lot of flat water sections, sluggish can be ok (or even preferable) as a beginner. I did A LOT of research on what boat to buy when I decided to sell my crossover and get more serious about WW a couple years ago. Jackson was hands down the best company for friendly and helpful customer service, and my wife an I now own 6 Jackson boats (picked up a new Karma S for a great price at the end of the summer - it hasn't seen water yet). Anyway, the Jackson crew steered me towards a Hero, commenting on it's slower speed being helpful for learning, and it's forgiving edges and volume. I think they were absolutely correct. My wife went from paddling a Rogue to a 2 Fun, and got to practice her rolling quite a bit more than I did in her 2 Fun. :) At the time I too was thinking about a Burn, but now that I've learned more I just don't think it's the best 'learning' boatâ¦though some like doing things the hard(er) way, which can work. I'm actually considering a Burn III this season for a more 'edgy' ride, but I'm waiting to try out the Karma S first. I'm 6' 135# btw.
Hope some of this proves useful. It sounds like you're on the right track, and a lot of the advice here has been really good.