You'll definitely notice how much better the slots area there. My first Reno trip I stayed at Harrah's too since it was comped and started winning on the first slot I played. The funny thing was when I first checked in I thought the casino was tiny, took a bit before I realized there was a bridge and a whole other side to it across the street.
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Agree with what everyone has said so far too. Definitely check out Atlantis (buffet there is good since the remodel), that's my all time favorite casino.

Peppermill and GSR are both worth checking out. I like the smaller casinos in Sparks too, just because I seem to win at them all. with a car you'll be able to get around pretty easily and quickly, even the drive out to Sparks takes like 10-15 min.

Tahoe is great to see for a day trip even just to see if if you never been, although don't go if weather looks to be bad when you are there, those roads are really hilly. Do your gambling in Reno instead of Tahoe though so much better.