Steam engines are a lot of fun, and Ministeam is a great place to do business. I prefer solid fuel over electric heating simply for the authenticity of the open flame (there’s supposed to be a FIRE in the firebox, not a dimly glowing heating element!), but of course there is a convenience and safety trade-off.
Be careful though, this is one of those areas where you can use up every horizontal surface in your home obsessively collecting stuff! Ministeam sells complete carnival and workshop layouts, which should give you an idea of just how far down the rabbit hole one can go. Then, the next step is the world of Stirling engines, which are great too (the multi-cylinder ones are downright mesmerizing to watch, and they are very rewarding to build from kits).
My only unsolicited advice is to exclusively use distilled (not filtered, not R.O., and absolutely NEVER tap) water in the engines, and always oil the cylinder, valves, and other moving parts before and after running (use the steam oil they sell, a small bottle will last a very long time). Do these things and the engine will last practically forever.