I keep buying games I have never played before.
Every game in my line up I bought (second pm, but first one I had never seen in person) without ever having seen in person. I still have yet to play my AMH due to a board problem and Alien just came home yesterday. Also, have not played my usa football (shopping it), but it should be similar to the ag soccer ball I got the same day.
Of those I'd say mystery castle is the one that never lets down. Simple ruleset. Fun layout. Great theme, sounds, and while it does not have any really expensive mechanisms in it, there are clever ideas to wow guests (hidden things in the translite, second gi, hidden ball capture on the right orbit that is only utilized sometimes. It is a very unique game and will only get rid of mine to find a nicer example.