I used JMA my first year in the Station and he did a good quick job. Cost somewhere between $105-115.
Last Summer, I did it on my own, worked out well, I did have some previous experience. Bought the Sealent at Home Depot as well as the applicator, my total cost was around $55-60.
JMA did a good job for us, too. Previous to that we had someone spray it on, but it was such a thin coat it was hardly worth the money. JMA squeegies it on and does a real nice job for barely more than doing it yourself.