Ooops, missed part of the question.
Real big gyms (not quite ones like Snap fitness, but ones like Total Performance, Metroplex, etc) have a lot of different equipment. In this scenario, you have lots of options and should you chose to switch your routine a year or two from now, for instance say transition from powerlifting to bodybuilding, you'll be able to switch from barbells to machines no problem in the same gym. Bigger gyms also have bigger spaces, so if you want to do any sort of high intensity conditioning drills, you usually have far more space to do those things in vs. a smaller, barebones gym (unless the owner has a huge backyard/driveway/etc). There are lots of more girls at these kind of gyms, however, my success with picking up women is zero (though my attempts are also zero!) at the gym so that's not really a big deal to me. Sometimes they have pools or other things that your girl might be interested in doing while you lift (she's still not warmed up to the idea of lifting). Prices vary, but more often than not they're less expensive than DIY gyms.
Smaller gyms have their own advantages as well. Often they were begun by people as a way to have a space with stuff that fits their needs that nobody else had. So they will have stuff the other big gyms wont have - special bars, bands, sleds, ropes, chains, chalk, belt squats, reverse hypers, GHRs, etc. Sometimes they are cheaper than the big gyms, but almost always they cost you $50 or up, so often it's more the exception than the rule. Many have great hours - 24h access - so you can go anytime in the day, during holidays, football games, whenever you want to! You can play your own music over the sound system, which is something not to be underestimated. Lastly, the crowds are usually more of your type, not douchy/questionable-gender types that plague most big gyms, and also tend to be more respectful.
