What type of corporate job is it?
I fly a Citation in part 91 corp ops. For many corporate operators the idea of "24/7 reserve" is more of a misnomer than anything else. Sure- there are the rare occasions when emergencies pop up that need immediate travel. But at good corporate jobs, it's uncommon.
Who are you going to be flying and in what capacity? IE is the flying 100% business, or is there personal travel for owner/executives invovled? If it's 100% business, the likely hood of unexpected trips declines.
See if they have a set policy towards being available/legal to fly- most corporate departments have "on call" periods set in their flight ops manuals. For instance, I am required to be legal and available for duty from 7am until 5pm on Monday through Friday, unless previously notified. Available at my company is loosely defined as fit to fly, and within 50 miles of the airport. There is no specific "report" time, however they want me to make my best effort should something arise (in 18 months of flying, an unexpected trip has come up once).
I left the regionals for a Citation job in 2005 (furloughed). While I miss working with a larger group of people, and I do miss flying a bit more, you quickly grow accustomed to the QOL and schedule that 200 hrs/year brings. We fly (maybe) one trip a week and have very few overnights (I spent 29 nights on the road in 2006, of which 9 were for training in ICT and MCO). Most trips have me home by dinner, which is great for spending time with family/friends.
I think the two biggest things that I miss are travel/jumpseat benefits and working with the wide and diverse body of people that are at the airlines. (I now work for a two pilot operation).
Simply put, if you want to work for a major/legacy airline, stick with the regionals and build time to move on. However I can say that if you land yourself in a good corporate job, you will find it very difficult to go back to the daily grind of the airlines- particularly this day and age.