Honestly it comes down to personal preference, but I'd say block exams are less stressful. We take one exam a week, and the problem with that is as soon as you take one exam, you immediately have to start studying for the next exam - which involves cramming 10-15 powerpoints worth of material in 6 days. You pretty much don't have any time to relax. On the other hand, my gf has has a block schedule and although it's stressful when her exams come around, she has a lot of free time once they're over. I feel like with 1 exam a week, you're constantly studying 24/7.
With that being said, some of my classmates do prefer having 1 exam a week. Again, it comes down to personal preference.
***also our 1 exam a week policy does not include practicals or quizzes, so you could have an exam, quiz, and practical all in the same week.