I haven't heard of anyone doing a DIY geothermal setup, so I have to ask, how or what did you do-it-yourself? You say you had a well driller come out, so you went with a vertical system. Did you install the line and grout, and do the unit change-out/hookup yourself?
I had the well driller, drill 4 wells, install closed loops into each well, grout the wells, and run the loops into my basement. I connected the loops into a manifold, removed some water from each loop and added an anti-freeze, and ran the manifold piping to my indoor unit. I paid the well driller about $5k.
I bought the indoor unit from a co-worker that is a ClimateMaster dealer, and had a few friends help me get it down my basement steps. This cost me about $8k. I paid $1k to another buddy the make the duct work transition pieces between my new indoor unit and the old heat pump indoor unit I replaced.
I reused the existing thermostat/communication wire, but installed a new programable thermostat. I paid my co-worker, the ClimateMaster dealer, for start up assistance in programming. It took maybe an hour.
I got lucky, because without my co-worker, none of it would have happened. The down side of DIY is getting service. Again I got lucky. It took a few years, but, I've found a local company to do service, if needed.
Since the installation was completed, I've had two issues. The first year of ownership, there was a circuit board recall. About year three, there was a circuit board that failed. I pay for an annual service agreement where they come twice a year to change filters, clean the coils, and other minor tune-ups. If I need additional service visits, I'm on a priority list.
The four loops into my house use micro adjustable flow control valves. They are used to equalize the flow between each loop. Initially they were left wide open, and the system worked fine. It seems many systems don't use this type of valving. My service contractor called me one day and asked to use my system for a training session for some new employees. If I allowed them access for an afternoon, they would equalize the flow between the loops for free. I did, and they did. I can't say that I've seen a noticeable increase in efficiency.