There's not much not to like about the G3X Touch. The thing really is a joy to fly with and Garmin is continually making improvements to the software. One example is that it didn't have a way to display AGL altitude. I (and I'm sure many others) emailed Garmin to ask about adding this. Pretty soon there was an update with AGL display included.
I guess the only criticism that I can think of is that some of the remote mounted components like radio and transponder are rather large and heavy compared to some of the competition.
I really like that Garmin has partnered with Foreflight so that I can transfer Foreflight flight plans wirelessly between my Ipad and PFD and also display ADS-B traffic and weather from the Garmin on the IPAD