We used Shake It Up (Chris, specifically) for my 40th birthday, and he was perfect for the event. Chris did a great job mixing the drinks on the menu we created. He kept up with a thirsty crowd all night (~ 35 people) with multi-ingredient cocktails (think black cherry manhattans, not rum and cokes)! He was very personable with our guests, yet unobtrusive. Arrived early to set up and his departure was not disruptive at all. Very communicative owner, and planning for the event was easy. Price was reasonable, and we will be using Shake It Up (and requesting Chris) for other medium-to-large parties we throw.
Seriously, use them. We could not have been happier with how it turned out.