Whilst I have never played this game solo, I can say beyond any shadow of doubt that it is well worth it for the multiplayer. Everything is balanced perfectly.
When somebody mines an ore node, an ore drops for every player. If you have one dedicated miner/crafter then everybody becomes relatively kitted out in a reasonable amount of time. Yes, RNGesus can come in and declare you unworthy of the correct ore nodes, and when it happens it sucks, but it's rare enough that it doesn't ruin anything.
The controls are tight, very tight. When you glub up, you know it's because YOU glubbed up. The only thing I wish is that I could rebind things a little more. Like having the dash be a double-tap instead of hitting E and Q. It feels strange to me personally, maybe it works for you though.
You will die, and you will die a lot. You'll keep coming back though. Grab a few friends and let the good times roll.