I gave this a try the other day.
Ambience: a bit underwhelming. They could have put slightly more effort into the decor and made it much more appealing. A bit too bright, and the wrong colour temperature. I didn't sit upstairs, which might be better, but first impressions count. 7/10.
Food: I ordered a caesar salad, potato tortilla, and 'Mexican' burrito. The salad was nice. A bit heavy on the red onions, but nice. Not smothered in dressing, and a sensible size, too - I hate being given bucket-sized salads that I can't finish. The tortilla was ... well, a pretty authentic tortilla de patatas. Like the salad, it had been made with good, fresh ingredients. The burrito was a disaster. I guess they'd seen a picture of one in a book somewhere, but had never actually eaten one. It came with a decent salsa cruda, and was wrapped in an actual flour tortilla, but it wasn't Mexican style, or even Tex-Mex. The filling was 95% rice, with some unrecognisable vegetation and (I think) some cheese. There were a few pitiful bits of chicken, full of spiky bones and dog-ends of skin, which tasted vaguely like Cantonese char siu. I had an irrational urge to beat the chef over the head with a tortilla press and show him how to cook it properly. 8/10 in general, 1/10 for the burrito.
Beer: I ordered a Bocq Gauloise Brune, for the very reasonable price of (IIRC) NT$160. Their entire beer stock is only slightly more expensive than you'd pay in the supermarket, and they have a lot of items you won't see anywhere else. Fantastic. Nobody does beer like the Belgians. 11/10.
I'll definitely be going back, and I'll try some different food. I'm guessing they were just having a bad hair day re. the burrito, because everything else was just fine. Recommended, especially if you're planning on a lot of drinking and not much eating.
They're a little hard to find. Locate the big 3C store. Facing it, look to your right and locate the Subway (on the same side of the road, about 50m up a slight hill). In between the 3C store and the Subway is an ordinary apartment building, up a flight of steps from the road. Cobee coffee is on the first floor of that building. You should be able to see their sign from where you stand.