I'm a corporate pilot and a member of the Air National Guard. My flight department has four pilots and does lots of 135. Long story short, it's a pain to reconcile the two, not to mention I got recall orders for five months next year. I will probably lose my job even though it's illegal.
I agree with earlier replies that the bigger the dept the better, with four pilots it puts a strain on things.
PM me and I'll give you more info.