I believe it's quite a snatch TBH. The game is Out of Print so getting the expansions could be difficult without scalpers. Many people consider the Worlds Collide Stand Alone set to be the best. I couldn't stand the simple theme of Dominion so I inclined towards Thunderstone's theme and art. Recently I received another deckbuilder called Draconis Invasion , streamlined gameplay with some depth and medieval fantasy superb artwork.
Most definitely worth it. I played my copy solitaire many, many times. Never got any expansions, as I've found the base game provide plenty of variety. Also, AEG has an app which will allow you to create more set ups beyond the 4 in the playbook that are supposedly balanced, as opposed to using the randomizer cards and wondering if you get a balanced set up.