You need to do more homework then before purchasing. If you don't need to fill your panel just yet then plan to attend EAA's Sun-N-Fun in Lakeland, Fl.My main concern is that I don't know/understand the differances between these systems.
It is scheduled for April 21-26th. That's the next scheduled big event that is close where you can get your hands on all of the units you are interested in . Find out what features/benefits you can't live without and which ones you don't need by trying them all. Twenty minutes with each unit and the decision may be very apparent. It's too big of an investment to roll the dice on. Price means little if your purchase doesn't fulfill your desired mission.
If you can't wait until Sun-N-Fun at the very least give our sponsors a call and discuss your requirements with them.
Kitfox Aircraft LLC also supplies at least two of the units you're interested in and they have flown them. John will give you an honest evaluation. Check with them for pricing.
They are dealers also.http://www.kitfoxaircraft.com
SteinAir carries all of the manufacturers you mentioned.