You will have an hour or so in the canyon and then the same ride back. Overall, it takes longer because it is a drive to get there (about 40-45 minutes) in an open air truck on a bumpy road. Only one group in the canyon at a time and 12 for each group. It is almost twice the cost and a world of difference. This may not be a problem for you, since you don't know differently and how it 'use to be.' So be careful to look at dates of reviews. Up until about 2-3 years ago, even a photographer would have time for some shots with no people or be able to take several portraits. If you are any type of photographer, you will need to take the photo tour. So none of just us as a couple but only us and the visitors we are traveling with. No longer do the guides have time to talk to you about the area or canyons and may only take 2-3 photos of you in the canyon and then keep you as a group in the photo. You are constantly being told to keep moving the minute you stop for a photo.
Each group contains 15 people per guide but they send several groups in during the same time slot. Although things have improved vastly since last year, the tours are crowded. In the past couple of years they have become very popular.
The Antelope canyons are the most popular and most photographed which leads to them being even more popular. So I've been going on them every couple of weeks. We have frequent visitors to our house in Scottsdale and invariable end up in Page for a slot canyon tour.