Biggest issue I had is that I can't swap between machines. So the only way to upgrade the AI on one, is to max it on the previous one. Same for all attributes.
You very quickly hit a point where you're block positive. Then literally all you do is mindlessly buy a new machine, fully max it. Rinse and repeat. Making the game a chore from that point on. Since there really isn't any choice involved anymore, just buy -> speed max -> multi max -> AI max.