I've got both of them in my gameroom sitting next to each other. Both are cool looking pinball machines, and I do enjoy both of them.
Haunted House-
I remember seeing this machine several times when I was a kid, the first time I saw it, I believe it was out of order. I remember looking at the 3 playfields and how amazing it looked. I also remember the double flipper buttons, and confused on how they worked. Anyways when I started collecting, Haunted House was on the top of my list for nostlagia reasons. It is a fun pin, but the ruleset, and layout is only average.
Black Hole
I didn't play this much as a kid, but once I had bought a Haunted House, I was interested in buying this machine. I scored one, and it is fun machine. I think it has a better layout, ruleset, and the BEST mult-ball on pinball machine, in my opinion. It also has a animated backglass, and speech.
Between the two, I would have to give the nod to Black Hole. It has a better replay value, and is fun to attempt mult-ball. Whatever one you choose though, be prepared to tinker with these machines, as they problematic, unless the mods are done.
-Mark