Jon,
I'm sure you could do it. There are no special tools, etc. They also give you most everything you need.
You basically just clean off the counter with a good cleaner like windex, etc. If there are any dings, chips, etc they could be filled with wood putty, bondo, whatever you have.
Then you tape around sink, backsplash/wall with the blue or green painters tape. You then roll on the black iron core primer they give you. It's weird painting a perfectly good countertop black but it is the first step. It is latex, so do not worry about a bad smell. This bonds to the countertop. Let that dry overnight or most of the day.
The next step is sponging the different colors on in order. You can't screw up, and they even give you a piece of black cardboard to practice on. You can get a different look dependent on how much of one color you use, etc. After a color or two it really comes alive. If you want any veining you can get a feather and do that also. If you are going for a granite look remember that granite is NOT uniform, so anything goes.....you are not shooting for perfection.
When you are happy with the look, (and if you're not, just re-roll the black on it and start over), let it dry and then you do the last step. You roll on a few coats of automotive grade polyurethane they give you. Let that dry and then put a small amount of silicone clear caulf around the sink and you are done. 2-3 days tops.
I can only speak for myself here, but we have been very pleased with this. It has held up VERY well, no nicks, scratches, etc. We have gotten many compliments on it and it was quick, easy and cheap. Dependent on the ratio of colors you use, style of sponging, etc you can get many different looks even with the same colors. The pictures do not do it justice. If you are considering it you are welcome to see it in person.....we are just a few miles south of you all in The Plantation.
DISCLAIMER- I do not sell this stuff and benefit in NO way here.....I just like doing house projects and if I can help someone else with advice I'll share it. Not everyone wants to spend $4-5 thousand on granite countertops when they plan on gutting the whole kitchen in a few years. I"m thinking for our next kitchen I might make my own concrete countertops....but that is another project.........;-) Well, time for me to get to work. I'm redoing my lanai....putting in new windows and a door, etc, today. Anyone wanting to help lift a ten foot wide window unit feel free to stop by.....
Frank