Free popcorn?! Probably the only thing that keeps me coming back.
I'm a huge fan of slush with tapioca, but this place just doesn't do it for me. Maybe it's the service (or lack thereof), the quality (again, or the lack thereof), or just the overall atmosphere.
I always order the mango slush with tapioca. I've been gravely disappointed by the mango slush here. Maybe it's because I've been spoiled with Ten Ren or even Genki in SF, but Green Grotto is just very inconsistent. The tapioca seems to be firm one day and really soft the next and the mango flavor seems to be that from a powder.
The service here is pretty sub par. The waiters/waitresses always look so unhappy and they take an awful long time to walk from the bar to your table with your drink (it's like 10 steps over... let's get real people). Prices are pretty reasonable though for the large sized drinks. No complaints there.
The atmosphere is alright. There's only one section with couch-seating, while the rest feature wooden tables. They play music of the Asian persuasion in the background and have your latest issue of the Chinese GQ in the bookcase. There's also free wifi, if you can manage to sit down and get a table during peak hours.
Will I be back? Probably not.