I don't know about other schools, but I feel like the pace at UOP is intense enough. Academics are not too bad if you've had a decent science background or are a pretty fast learner. The lab work's the real killer though. You have barely enough time in class to do it all, but that's only if you're perfect and get it on the first shot. Pretty rare though for people to get it done. The majority of us end up staying after school or coming in on weekends, and sometimes even if you do get it right, there's always the chance that you drop your cast and crack a die, meaning you get to start all over.
For example, on Wed afternoon, our pre-clin fixed instructor told us to wax up 6, 7, 19, 23-26, make 4 casts, mount two of them, make a splint, provisionalize 6 and 7, and cut a pfm prep on 27 along with a temp, all by next Wednesday. Doesn't sound like too much, but we have 10 other classes to worry about, including an operative practical and biochem midterm. And also all the other fixed stuff we have due wednesday which could include a cast post core on #6 and wax-up/investment/casting/cementing an FVC on 18 if you screwed either one of them up the week before. None of us are experts at this stuff, so it still takes us like an hour to do what a real dentist could do in 10 min.
The faculty tries to be pretty understanding and nice about it...try being the key word. They are receptive to our requests and complaints, plus they're nice in the most part. Keeps most of the students happy despite the workload.