I have a 8700 and a Black Razr. The 8700 is for work (both data and phone) and the Black Razr is my personal cell. I do not like having one number for both use and the fact that if you leave the company, you may not take the number with you (even if it was yours to begin with).
The only issue I have with both is using 2 bluetooth headsets when I'm in the car. Yes I know I can forward one number to another but how often do you remember to do that? I only do it on long drives honestly and not the quick ride to the store.