Uncle J.
Yelp
Overall, our favorite bar while in Old San Juan/Condado for a week (and doing our fair share of drinking). It's easy to get hung up on what's a dive bar, what's not a dive bar. My dive bars are typically prone to serving only cheap, watery beer and strong drinks made with mid-shelf liquors at best. This is not that place. The beers were can/bottle only and there wasn't much of a selection so that fit the bill, but our bartender was making some truly great, creative drinks. Left to his own devices to make us whatever he liked, they were simply the best cocktails we had all week. I wish I could remember his name, but alas (it wasn't Christos). We have some great bars in Portland, Maine (it's near Boston :)) complete with award-winning "mixologists", and this place, at least with this dude behind the bar, was definitely on par, in our humble opinions.
The atmosphere is certainly what people must be referring to when they call it a dive, and they're not wrong. It's tattered, written on, and run down in the best possible way, and it was pretty refreshing after finding many of the bars to have more of a nightclub vibe. Even Polo Norte, a self-described whiskey lounge, was fun, but a little weird with the vibe and the blue light, etc. (the super nice bartender there did point us in the direction of El Batey though when asked about his favorite spots, so many thanks to him)
I was with two feisty ladies and there were some drunk dudes there flirting with them (it is a bar), but harmless and funny. In fact, everyone drinking there, at least on this particular night, was easy to talk to and not aloof or smarmy as you can sometimes get if somewhere is "trying" to be a dive bar.
I can't claim to be any kind of expert on the cocktail scene in OSJ, but for a laid back vibe where you don't feel required to have a silk dress shirt on, where you can still get some amazing cocktails, I would definitely recommend this place.