I generally try to stay out of these comparison threads but just this once!
I have a Bold 9000 and a 3Gs (both on Exchange) and my wife just got the 9700 to replace an aging Curve. Both the 3Gs and the 9700 are very good devices and excel in different areas. As with another poster I have the best of both but I find the BB to still be the best for business use if you have a significant requirement for the Exchange (ie email, tasks, calender, etc) functions and/or you travel for business regularly.
The 3Gs shines as an Internet information/data device. Yes, it does Exchange sync fairly well, but I use it mainly for data, be it weather, news, stocks/financial updates, sports updates etc. As was stated the apps (at least some of them) are fantastic and I find that the same app on the 3Gs is generally much better than the one developed on the BB.
So, to answer your question.......................it all depends