The only issue with Mendez is that you'll want to bring a full water bottle, because they don't have a water fountain (or you can buy a bottle of water for a dollar from them). Also, the locker rooms are not that great, very cramped and with bad showers, and you have to rent a towel for a dollar if you don't bring your own. Also, Hector speaks very little English - virtually none - which can cause some comprehension issues when he's correcting your form or you're on pads with him.
That sounds worse than it is - I go there, and have trained with Hector, and I like the place. But if you're looking for a bigger place, with a huge locker room and showers and towels, and you're looking to pay a lot more money (like $250 a month), and you don't mind going down to Rector Place, Trinity Boxing is an alternative.