Ultimately it comes down to personal preference. You can make it work with many different choices.
You can also use stirling engines with solar collectors if you don't like dealing with fluids. They're also more expensive (like solar), but simpler to deal with. So that's a third consideration.
Geothermal plants are even more cost effective than solar collectors, and a popular main power generation method. You need some geothermal patches for volcanic gas, but you should be able to find plenty. The patches never drop below 25% richness, so they're infinite, and you can use speed beacons to get more out of each patch. So that leaves plenty of patches for geothermal plants.
Yes, solar is more UPS friendly than any other power generation method, but most people can have quite large bases in Nullius without dropping below 60 UPS, so it's not a universal concern. If you're building a big solar farm, you may as well put some wind turbines into your grid-aligned solar blueprint.