I have had two, an Evolution 1000 Pro on the Aztec and a 1500 C3 pair on a Navajo.
Brian Cook at Bournemouth Avionics, Lee on Solent, is the expert and I strongly recommend him. He is probably not the quickest, but he does a great job and really knows what he is doing. I met the Aspen European Manager at Friedrichshafen and he had nothing but good things to say about Brian.
PM if you would like to chat on the phone.