I flew for Air Wisconsin for 23 months and have been in my current 91 job 22 months; you'd have to drag me kicking and screaming away from my current gig to go back to a regional airline. Yes, its much different than the airlines in almost every way (other than flying Point A to B) and as you well know, there are corporate pilots that want nothing to do with airline flying and some airline pilots that want nothing to do with corporate flying. I personally think having an airline background helps give a bizav pilot perspective (in customer service or rather how not to do it, flying in challenging weather, etc) and there is no denying the quantity of quality experience you can gain over a short period of time at a regional airline.

If you did leave your job, you wouldn't be the first person to have a career path of entry-level 91/135, regional airline to build turbine multi time, then back to the 91/135 world with a substantially fatter logbook and experience bank (and lighter checkbook)!

That said, Netjets will require a bare minimum of 2500tt and an ATP; will you get both of those in a reasonable amount of time at your current job? How long until you can upgrade to the King Air?