We did the tour several years ago and I highly recommend. It was an all-day affair and you'll need to wear jeans and a rain jacket of some sort. Shorts might be OK as long as you have a jacket. It will rain the higher up you get (rain forest-like). They serve you breakfast about half way up and you come down the mountain on bikes stopping when you want. The bus follows along in case someone doesn't want to finish the ride on their bike. The scenery is spectacular and we were allowed to take pictures and swim in a small waterfall toward the bottom of the tour.
Yes, we took it a couple of years ago and it was great fun even on a rainy day. They gave us ponchos and it was a little chilly on the way down but it was a very neat experience. You got to see a little more of Jamaica and see the coffee being grown. It was a full day away from the resort. I'd imagine on a clear day the views would have been amazing. Definitely not strenuous.