I dont do consulting as often now, but when I do need some money, I do UI consulting. It's a little annoying IMO, especially with all the restrictions and working with someone who has no taste in design whatsoever yet they still keep on pushing their ideas forward....But, here are the somewhat positive sides I've managed to branch out from it:

* The ability to keep on working even though you want to kill someone how annoying their project seems to be.

* The ability to keep on iterating small changes which unfortunately are just warm ups to even more iterations.

* It's very annoying, even though you are probably making a good chunk of money. Great thing about it, once you move onto your project/startup(which I really suggest you do as soon as you have a proven idea and market) you'll pretty much love it and become very good at building something good.

* Oh, not to mention that you'll have a better outlook on things after you've worked on a few projects for clients.