I used to live around the corner so I think I have a pretty good idea about Umi. Some staff are pretty on top of things, some are pretty "doh".
The food is hit and miss and it depends on what's up, they never had a real consistency there, when it was good it was great, when it wasn't it was borderline bland or just *meh*
It's more of a coffee/tea place unless they have extensively overhauled the menu since I was there last.
The dipstick element can be there in full force on some days. It was very exasperating being exposed to some people's opinions at too loud volume when in there to read/study/chill with friends, but I still went because you can't blame the staff for tolerating loony tunes characters when they come out for sustenance.
Cons: meh look, that dolt playing piano and singing, the creep content on occasion