Oasis is nice, I've only been there once looking for feeder guppies. But I lost interest in Sierra the last time I went and they had a capybara for sale. Its turning into a regular pet store.
It's not a capybara, it's a mara, but it's still not an animal they should be trying to sell. Their prices on exotic mammals are outragous. They need to learn you buy animals at a wholesale price, mark them up to retail price, and then you sell them. They are buying retail from some one else, then putting a retail mark up on a retail price and have to sit on an overpriced animal for a year or more. Not cool.
Reno also doesn't have any good exotic vets that I'm aware of to support these animals.