Decent club, downstairs and low ceiling. Not a huge capacity, about 600 I think over a couple of rooms, so will make it a good night for someone like Mano Le Tough.
It has a bar upstairs or the City Cafe directly opposite is a bit of an institute in Edinburgh as a pre clubbing bar.
Bar Soba is popular but about 10 minutes walk away, always has DJs at the weekend. 99 Hanover Street also busy and directly across from Soba.
There is also a decent Ibis just up from Cab Vol and the City Cafe. If you stayed there, you could stay in the one street and have a decent time to be honest.
Let me know if you need help with anything else.