I think I love every B/W three flipper game. I'd have them all if Inhad room. After owning TS for a while I can definitely say it's a frustrating pin sometimes if you're not a great player. It doesn't make it not fun, though. It's my favorite in my lineup currently. When I'm tired of getting my rear handed to me, I flip on IJ or CV and have a fun game. I don't have much time on Congo, but what I did play of It I enjoyed. I thought the lower playfield was pointless. I think the mini playfield on TS is light years better. The volcano shot is very satisfying, though, and the game is not as intense as TS.
Cliff notes: if you can swing it, have both. If not, decide if you want a dark themed motherfucker of a game, or a lighter themed game with longer ball times. It's not like one is worth $8k and the other $2k, they're only about $500 apart on average don't let the money keep you from enjoying pinball