We like the concept of free walking tours as the tour guides have the incentive to do their best and we have attended many of them. At best the tour guide is funny and points out those little things a tourist won't notice otherwise. Our guide did this too (see the painted window with a man staring to the market place, the trumpeter finishing abruptly etc.) But on average he concentrated a little too much in historical trivia for our liking. We attended the tour twice (old town + jewish quarters) with the same guide and on the other day he seemed more relaxed. We were given the possibility to powder our noses only during the jewish quarters walk and possibly because of that a few of the group went missing in action and didn't rejoin us during the old town tour.