It pretty much comes down to wasting/investing tons of time vs investing a lot of money
If you got either to blow(and you want to blow it), then you'll have no problem with Warframe's system. I'm extremely bored with it. PvP isnt too interesting, missions are extremely repetitive, and the pay off is very little for the time being spent. It could be argued that i'm not grinding "correctly", but its hella boring doing it the "right way" (although grinding is boring in general).
With that being said, the Obex(systems) will always be one of my favorite game weapons for a while. Also, Kubrow looks meh. Its okay