I have a 3 a 4 and an Inspire. If you want reliable take the 4, the inspire has upgrade issues, and transmissions issues, as far as changing cameras, most don't work the Z3 is junk and the supposed better cameras, can only use three lenses and you have to add counter weights to them, in addition taking the gimbal on and off of the inspire wears out the connecters. Also if you are traveling by plane you can fit a 4 in a backpack under the seat, an Inspire always has o go in cargo hold, I have the best cases money can buy, and I have still had my inspire broken twice, yes I have insurance but that doesn't do you much good when you show up at a shoot.