I recently completed installation of a Stratus ESG transponder so I thought I would post my comments:
I was somewhat reluctant to go with Stratus because I would like the flexibility to use other Tablet displays, but since I had already jumped on that bandwagon with a Stratus II receiver, I just continued to drink the cool-aid.
Also, with the FAA rebate this is a pretty economical way to go especially if you really needed a transponder upgrade anyway. The advertised cost to an individual is $3000, but I believe they are giving their dealers a $1000 discount, so the "turn-key" installation was $3000. I also bought the Stratus receiver interface cables.
One small problem I had was communicating to my avionics shop that I did want to interface my receiver. They misunderstood me and did not order the interface cable. Also it turned out you actually need two cables and the installation of another coax connector on the ESG tray to complete the installation. Appareo is not at all forthcoming with detailed information on their web site which would have definitely helped me communicate what I wanted to do. One other thing I did not really like is the design of the GPS antenna. It is a big square thing and does not really look very nice on the turtle back next to my other GPS antenna. If I had know what this thing looked like I would have looked into getting another antenna.
I am pretty satisfied with the final installation. The transponder works as advertised and I have the Stratus receiver mounted under the panel on top of the battery box in my 6. I seem to be receiving more ADSB stations than before with the Stratus box on the glare shield. I flew the required FAA test flight (which was interesting since the controllers seemed to have no idea why I wanted to do all of these stupid antics.) Got the check from the FAA in the mail, which is sort of amazing. I just really didn't think they would come through.
One final comment. Even with everything working as advertised, ADSB is still no substitute for TCAS and good eyes. Any traffic not in radar coverage is not going to show up (unless of course they also have ADSB out). Several times I have been watching traffic en-route or departing my home field as I was en-route and as they descend toward the pattern they disappear.