I picked a random spot in New York state. It looks like the solar generation in January is about 68% of July. As solar keeps getting cheaper, one option is to just install more solar.
Don't get me wrong, there are still issues here, like snow or back-to-back-to-back cloudy days. But the rate of a price change for solar has been pretty dramatic.
I'm just generally impressed by their community efforts vs cFS. They really do their development on GitHub - not just a place to push out source, but issues, PR's, discussions.
FPrime has some rough edges, and it takes a bit to get used to, but the team's interest in continually improving the core for a wide range of users is the differentiator.
The most expensive tooling was the two floor jacks I purchased to make the process easier. The software needed was available from the manufacturer for a reasonable fee. The battery pack itself was surprisingly modular and simple to dismantle for repair.
I don't many things GM has done, but (at least back in 2010) they did a good job of letting owners do their own work.