Spend a year working from home and you'll start looking at cafes with new eyes. Mine always dart around for available plugs because no matter how much caffeine you consume you won't last long if there's no place to keep your laptop juiced up with power.
At Tinto we snagged a large table with easy access to an outlet. We stayed for more than six hours and never once did the staff so much as nudge us to be on our way. Instead they sweetly served us mint tea, hot chocolate, whole wheat English muffins with cream cheese and jam and my favorite - the burro chiquito, a wonderful confluence of sweet potato, black beans and goat cheese held together in a grilled tortilla.
The free wifi was reliable and for the most part pretty quick. There's plenty of room at Tinto too - I was surprised with its spaciousness. And in case you're not there to work, they sell magazines and serve wine.
Tinto's pretty much got it all!