We see our kids for about 80 minutes every other day. It is good because we can use a good block of time to develop a major lesson or have several different activities during a period. We can also combine our two classes for a two-hour block, if we wanted to show a movie for example. We have a simple schedule with doubled periods Monday-Thursday and single periods on Fridays. We vary the length of the class periods if there is something special going on and if we lose a period due to an assembly, etc.
Some advantages are fewer preps per day.
You gain a lot of time which is usually taken up with the kids getting out their materials etc. The students benefit from having more time on task and seem to really like the longer periods. This year the practice was starting to be adopted by a couple of ninth grade teachers and some other teams in our building. Hope this helps. Here's Our Rotating Block Schedule . . .