I need help deciding on a car. Which one is more reliable, and overall better option?

I have about $2,000 saved up but my goal is drop a 3,500 - 5000 down payment on a car. My #1 pick is a 2015 Honda Civic ex, but the ones available to me are kind of pricey. If I can't get that my next 3 picks are either a 2015-2016 Toyota Corolla S, a 2015-16 Hyundai Elantra SE, or a 2015-16 Mazda3. The Corollas by me are in a similar price range as the civics and if I were paying that much money in a car, I'd much rather have the Civic. Opinions? Suggestions? Anything about the Mazda3?

All the vehicles you have mentioned have huge potential. All four are of good quality and had great initial reliability ratings. However, you should only consider which have been fully and properly serviced and maintained the last few years. If the seller can't show you proof of such it should not be considered.

They are all pretty good.

The Mazda 3 id the most fun car of the lot. The Civic is reliable but boring like a fridge.