COMPARISON
I have flown the aircraft and of the three I prefer the A-star. For passenger comfort, noise,ease of entry/exit, and performance this is the best aircraft. Your personal preference will of course be the final deciding factor. For charter work the A-star , I think, gives you the most flexibility. For instance, take the doors off for photo-work, the large cabin area for internal cargo, and the choice of hooks for external load work.
Our company has operated all the aircraft in the past. We now have 18 of the A-stars and none of the others. The support has been an issue. Depending on your location, it may not be as difficult as you think.
All three are good reliable aircraft. Check performance numbers carefully at the loads and altitudes you will operate at. Think about your needs and how each will answer those needs. You can't go wrong with any of them.