Some Oxbridge students find the tutorial system stressful, usually the ones uncomfortable exposing their weaknesses.
Have you been or are you a tutor at Oxbridge @poetryandwine ? I am and I find the above rather harsh, or at least off the mark.
I'd say most of my new students find the tutorial system stressful at first and then at various times throughout. That's not because I'm an ogre in a gown who is determined to make them look stupid or reveal their character flaws. It's because it is a very different system to what they're used to. Pretty obvious, since few students are taught 1:1 or 1:2 during their school years.
They're not used to the intensity of mostly listening, having to answer all questions, and not having a group discussion. This includes students who do know their stuff and have prepared very well, not just ones "uncomfortable exposing their weaknesses". I've never had many that fall into that category, the application system weeds many out I imagine. Students do squirm when they haven't adequately prepared, but I don't see that as being uncomfortable exposing their weaknesses, I see that as them being silly. They know themselves it's stupid to do that, they won't be getting the most out of me or the tutorial so it's pointless. But they're young, and there are so many temptations to do things other than study, so it will happen now and again.
Students do also love the tutorials, as well as finding them occasionally stressful. It's a huge part of why many want Oxbridge, it's our USP.
OP, I'd say it's impossible to know whether it's worth applying without visiting at least once, ideally both Oxford and Cambridge, and talking to students. Someone above made a very good point about cooking and cleaning and travel not being an issue for the whole 3 years, so the students have more time to focus on studying or sports or socialising than at other universities. It's a unique setup and it's not going to suit everyone.