I looked at both the Aspen E5 and the two Garmin G5's while I was at Oshkosh for the week. Went to all the display's and drooled over them every day. The Aspen looked to my old eye's to have a larger, sharper display. As far as installation, The Garmin's and Aspen both require hooking up to the pitot static and your chosen rado's/Auto Pilot. (The Garmin has no ability to hook up to legacy radio's where the Aspen E5 does if you choose to add the ACU for 1K more. The G5 will sync with legacy Auto Pilots if you purchase the GAD 29b for about $500.00) and they both come with the remote magnetometer that needs to be mounted. The Aspen has the RSM and Garmin has the GMU11. So I just do not see that the install cost would be any different. Now the Pro versions of the Aspen might need more installation time. I decided on the E5, and the Garmin GPS175, Sarasota made me a deal at the show for $4100.00 each plus a complete wiring harness shipped with no sales tax. I think they only made me that deal to get rid of me, because they were spending a lot of time wiping my drool of the G5's and E5 displays. My install should be simple as I will keep my legacy radios and their indicators, and only hook up the E5 to the GPS175. I hear every one talk about the fact a G5 comes with the HSI and that the E5 does not. Well the E5 might not have the traditional HSI but it has all the information of an HSI just displayed a little different. Both the E5 and G5 have a slaved DG with GS/LOC display capabilities, so is that not an HSI? If you are going all Garmin then the G5 is a good choice, I kind of like the open architecture of the E5.