In terms of functionality the blackberry wins hands down...but beware that in this case the blackberry is an entry level or budget handset, where the nokia is a flagship model. As much as this has no real effect on the feature list (like I said the bb is the hands down winner), but the difference is noticable when it comes to things like the phones exterior (nokia is solid metal, where the blackberry is plastic) and also the nokia wins in terms of screen resolution and camer quality! If you want a serious smartphone to get the job done go for the blackberry, if you want something prettier that's more of an all rounder, the nokia might be better! If you're getting a 24month contract check the prices of the curve 8900...a more high end bb with a better screen/look etc!
Hope this helps!