Well, if you think that changing slot machine will gonna change your luck and give you the edge you might want to think twice.
Slots are not exactly known for the best house edge among casino games, on the contrary you will most likely lose while playing even more.

But despite that I like to play some slots from time to time I can really recommend the one slot machine I like - Satoshi's Secret.
You can find it at every good bitcoin powered gambling site.