I own and play this quite regularly, bought it in early Beta.
Butjam- a controller is compatible, the 'partial controller support' mainly refers to the in-game profiles for various devices so depending on what you have, you might need to do some button re-assignment yourself. A HOTAS is by no means needed, but definitely helps in combat and makes piloting a bit more intuitive.
It is a great game if you're into the complete open world type game. This game will not feed you ANY missions, will not tell you where you need to go and what you need to do. Its story is more of a backdrop and not a central feature. If that doesn't sound good to you, then don't buy this game as you will not enjoy it.
That being said, the dev is quite good at adding in patches and enhancements to the gameplay (can't wait for mining drones so I can avoid that damned grind) with paid expansions featuring planetary landings and other such goodies on the horizon.