1st things first, if at all possible (ie, the concrete hasn't been poured yet) you're absolutely gonna want a vapor barrier everywhere you plan on having any sort of coating. It's a simple plastic layer between the earth and the concrete, which prevents water from being drawn up and becoming trapped between the porous concrete and non-porous coating, which can cause bubbles and eventual cracks in the finish.
Second, get it done professionally. Professionals have the variety of surfaces and the tooling & expertise to grind, mix, and apply it properly. The DIY kits have somewhat of a reputation for inconsistency in finish, and are not as durable. Not to mention, the chemicals used in commercial grade flooring are some of the nastiest around. Additionally, professional grade coatings have a longer life, and given you have a vapor barrier, are often warrantied/guaranteed by the installer for 10 or more years. Without the barrier, you might be looking at a 1 or 2 year guarantee.
My dad just went through this decision making process with me about 2 months ago, so if you have any more specific questions, feel free to ask.
Edit, from the post pics of your garage thread, how the finish turned out: http://www.e90post.com/forums/showpo...66&postcount=6
It is not as dull nor gritty as you mention you would prefer, but like I said before, the contractor has tons of samples to choose from.