Well, it partially depends upon how much time you have. I wouldn't leave the regional until you have the minimum hours required for a fractional.

Avantair (check out www.avantair.com) is a fast growing fractional and one to consider (my preference would be Netjets but, as you would expect, there is a long line for Netjets after their recent new contract):

Avantair Minimums requirements:

2500 Total Time
1000 Multi-engine
250 Instruments
100 recent multi engine turbine or type rating
250 Hours within the past 12 months
Airline Transport Pilot preferred
First Class Medical
Current Passport
FCC Restricted Radio/Telephone Permit

I would stay at your regional at least until you meet those minimums. How close are you to 2500 hours? Plane Sense (also known as Alpha Flying - www.planesense.aero) will probably hire you with fewer hours onto a PC12 and then in 4-5 years you could fly a new Grob jet. The point is that you want to get the minimum hours necessary to make these jumps to ensure you have options.

I hear what you are saying about flying a Bravo. Not a bad option either. You get jet time but I would only leave the regional for that job if my upgrade time to PIC was short. PIC jet time (and a decent amount per year - 500+ hours) could make you more attractive to some of the more picky fractionals like Netjets and Citationshares. To sum up, the Bravo would make sense if you could upgrade to PIC soon and you could get a good number of hours per year to get you closer to what the fractionals would look for. I am sure that after flying the mighty CR7, the Bravo will underwhelm you in terms of its power.