There are two excursions that we can do (thru the cruise line) and I am not sure which would be better:

1. Chacchoben - approx 4 hour excursion including the 90 minute drive (one way).
or
2. Kohunlich & Dzibanche - approx 7 hour excursion to the two different sites including the 2 hour drive (one way)

Has anyone been to these ruins and care to describe your experience? Thanks in advance for any advice!

I haven't done either tour, but here are some reviews of the tours you are considering.

Chacchoban ruins Links

http://www.caribbeanportreviews.com/CostaMaya2.htm

http://www.caribbeanportreviews.com/CostaMaya8.htm

http://www.caribbeanportreviews.com/CostaMaya10.htm

Kohunlich ruins links

http://www.caribbeanportreviews.com/CostaMaya15.htm

There are a few more on the site as well. Hope these help.

Tom