I've popped into Los Locos every now and again for fair few years now, for a few drinks after work. Its unpretentious, relaxed and the staff are friendly. The drinks are good value, and whilst I haven't really eaten anything other than the nachos, I thought it was good quality and good value. I think thats the thing about Los Locos, its not trying to be anything its not, and believe me there are plenty of restaurants/bars that are certainly worth the money you pay, especially in Covent Garden.
I like Los Locos is I want to get away from the hustle and bustle of Covent Garden, where I hear what my mates are saying, grab a seat, and enjoy a few pre-home-journey drinks. They do a great happy hour deal on drinks and food, which is in fact longer than an hour. Sweet!