After playing Snowrunner a few times it's hard for me to see this predecessor as a full-fledged game. I'll admit: Spintires has heart. It does the depressing Soviet atmosphere like no other and the mud physics are even more impessive than the sequels. But, all things considered, it feels devoid of direction. It feels like a really (really) good tech demo. So, would I recommend it? Kinda... but that all depends on what you are looking for in a game...
Some big improvements Snowrunner makes involve game structure, incentive and a desperately needed fun factor, which I find Spintires to be lacking. So you might want to save your hard earned cash and get one of the sequels instead.