You will get a wide variety of answers, only because it's such a broad question. I'm with Options and all the crews I meet out on the road are great people, not only our own crews but those of Netjets and Flexjet as well. The fractional industry is a new niche right now, and it's selling well. Even in times of this downturned economy, we are all still taking delivery of new aircraft. I'm anxious to see what happens when this economy turns around, it'll go gangbusters!!
You won't make major airline type salaries at the fracs, but you'll live comfortably. Senior frac pilots make low six figures at any of the companies right now, and the potential for higher salaries is very realistic. As was previously mentioned, Netjets is negotiating pay right now, so likely they'll set the bar. I hope they get everything they ask for, it'll only help the other companies. Schedules are very similar between Netjets and Options. We have an eight on, seven off schedule; and NJ has the seven on, seven off. It gets to be a long time on the road, but when you fly alot the time goes by fast. Seven days at home is a long time too. My wife is sick of staring at my ugly mug by about day five. When it's time to go back to work, I'm ready to fly again.
The best answer to your question was given by Falcondriver: the one that hires you first. Good luck.