I'm a very active Brazilian Jiu-Jitsu and MMA practitioner and wouldn't ever think about quitting or changing into some other martial art.
One thing about choosing which martial art to practise is thinking about what you really want from it: e.g. effective self-defence abilities or just want to get some exercise?
Of course there are many martial arts which offer more or less of the both, but one should still consider that many martial arts these days are not like they used to be hundreds of years ago when they were actually used in real combat situations. These days many of them resemble more of an sport or an artform rather than an realistic and effective combat skill.
Of course I'm biased when saying this, but BJJ really is one of the most effective martial arts these days (no matter how gay it is). There was some criticism about a grappling art on the streets but BJJ does have many options. You don't always have to go for the armbar and get your calf chewed on.
I had to defend myself against some random drunken guy day before the christmas eve (!) and when he started throwing punches I clinched him, took him down, mounted him (=sat on top of his stomach) and pounded him until he apologized. And thats just one way of dealing with a situation like that. I always try to avoid fighting as much as possible and I'm not really proud of what happened, but just wanted to share a concrete example of one of the many ways BJJ can be used.
Basic guideline of mine for choosing an martial art would be that pick an martial art which has as much full contact sparring as possible. Otherwise it really can't be considered very realistic for self-defence purposes. E.g. for striking I would probably go for Muay Thai or traditional boxing. I also heard some good things about Kyokushin Karate. For grappling of course BJJ or wrestling.