I am just about convinced I'll go the Dynon route (about $10-15k less for roughly the same features and I can do the install myself if I want to)
Not on a certified airplane you can't (do the install yourself, that is). And if you have an experimental, you can do the Garmin install yourself too.
Also, from your avatar, it appears you fly a Cardinal RG. The GFC 500 is currently in the process of certification for your plane (I would expect it'll be done by Sun-n-Fun in April). The Dynon autopilot is currently only certified on the 172 and some Bonanza models, and it'll likely be a few years before they get down to the Cardinal RG.
I don't see how the Dynon can be $10-15k less than the Garmin, where the most expensive Garmin solution (10+7 with EIS) costs about $15-16k.
Assuming single 10" display, backup, and autopilot for installation in a Bo:
Dynon:
"Basic Package" (includes 10" PFD + D10A backup): $9,140
Autopilot (3 servo): $6,310
Engine Monitoring: $1,859
IFR Connectivity Kit: $499
STC: $2,000
Total equipment cost: $19,808
Garmin:
G3X Touch 10" w/6 cylinder EIS: $13,395
G5 backup display: $2,249
GFC 500 (3 servo): $8,995
Total equipment cost: $24,639
So, the difference between the cost of the equipment + STC for certified aircraft appears to be under $5K, and the Garmin combo is available for many more aircraft. If you don't want an autopilot, the list of aircraft available for both solutions gets much longer, but Garmin has a huge leg up on Dynon when the autopilot is included.