Came here for Happy Hour karaoke with a large group of friends on the weekend and I had a fairly good experience. The Happy Hour ran from 3pm to 8:30pm and it was roughly $13 per person after tax and tips, which also came with a non-alcoholic drink of our choice.
I liked that the location at right by the Dundas/Spadina major intersection, so it's easy to commute by street car from both streets. If you're driving there's underground parking at the Dragon City for $15 a day.
The song selection for English songs was decent and the system on the touch-screen menu was pretty easy to navigate. The search system sucked just like most karaoke bars that I've been to, however.
The room was pretty and the disco lighting was great. The furniture was in decent shape and no complains on the sound system as well. I liked that we were given disposable covers to put on our mics for sanitary reasons and for better sound quality.
If you're looking for a cheap and decent quality karaoke bar for Happy Hour, then 8090KTV is a great place to go. However, I don't suggest coming after the Happy Hour as prices go up drastically and the food and drinks are quite over-priced.