I use the Roclite 315. Seemed to me to be the best of lightness, durability and sole protection. If you won't be on rocky trails or you already wear shoes without a rock plate then you could go with a lighter model.

But I agree, fit is the most important thing for any shoe you try. Not sure how many other brands do this, but you can heat the heel cup with steam then put them on and walk to get a better heel fit at least.