You won't be using it's stab bonus, when you have a better slash bonus, will you. The difference between both stabs is much smaller than Rapier stab vs. CLS slash, which is the main reason why some people want CLS (increased accuracy, and str of course), however the speed difference stays the same. Well if you were only getting one of the two, then the stabbing would be nice for dragons. Stabbing of Rapier or CLS? Not sure if CLS will be that much better than zammy spear, seeing it's slower. I'm actually not sure what I will get either. Rapier will probably be better in DPS for most things, even Bandos solo, I personally believe. However, I'm 138 combat now, and I think CLS will be much more fun to do slayer and pvp/minigame with, because of the high hits and higher accuracy.