I am not going to be popular for saying this, but the most overated games are anything with a bally/williams sticker on it,with an asking price of $5500 or more.
* I SHLD SAY THE PRICES ARE OVER-RATED, NOT THE GAME ITSELF.
Sure bally/williams have a deep rule set, and some machines like monster bash have the best looking colours/cabinet etc known to man, but the prices now have got to the ridiculous stage.
When looked at in context, who would rather have one pin only or 4 other great titles.
example,
1 x monster bash  or 
 
1 x last action hero
with 1 x fishtales
with 1 x freddy krueger
with 1 x frankenstein. (these x 4 titles/EXAMPLES can be picked up for around the $2 grand mark in great nick) 

*thats why i have 20 plus pins which are absolutely fun, fun, fun, instead of 3 x totally over-priced bally/williams.
BUT, i want it known, BALLY/WILLIAMS are superb pinballs, no -one can dispute that, JUST OVER-PRICED.
**ohhh, AND IF someone has 3 x bally/williams high end pins, instead of the 20 others 4 example, there is nothing wrong at all there, it JUST GETS DOWN TO PERSONAL CHOICE....  ...NOW, WHO STARTED THIS BLOODY THREAD, WE ARE ALL GOING TO GET IN A ARGUMENT NOW.LOL.LOL.

Was talking about this topic recently and totally agree with your comment.Yes it is a personal choice as to what some people will pay for a certain machine if its something they really want.For me i would rather have more good machines for your money ,which is also more variety than one.