The moderators aren't going to like your cost info. But that is a very impressive government credit.
Your contractor or distributor should be able to give you 3+ references in your exact area with the exact same or very similar systems. Ask them if geo works for them. I would also ask about any problems they have had.
Be sure that you run the numbers based on actual proposals to see how long it will take you to recover the premium you would be paying. I did this for geo proposals versus a high end DFHP taking into consideration our energy life style. Wouldn't recover it in my lifetime probably. And I was biased towards geo with hot water recovery.
There have been some posts on this forum that provided ground temp data for various locals. This is a big factor.
I would make sure that your contractor is very experienced with geo. This isn't your normal tech expertise and there definitely seem to be major issues when not designed and installed properly.
Here is a web site for a gung ho geo advocate who is an architect and long-term energy consultant: www.dougrye.com. Do your research before leaping.
PS: My understanding is that a lot of Toronto is actually cooled by geo, but they use Lake Ontario as the heat/cooling source.