which traps do you like better?

Actually it depends on the trap, if it’s a really well designed trap then it always catches my eye, it is rather fun to watch single traps because most people panic like mad and waste most of their time trying to do things that will never work only to notice they are about to end in a pile on the ground. On the other hand most group traps you have a chance to work out how to do things together or go against each other, either way it hardly ever works out well for both parties. I must say my fav traps have been single ones.

I like some of the single-person traps, and to me they feel like a truer test of the survival instinct that interests John Kramer. The lengths people are willing to go to in order to get out alive

However the multi-person traps are fascinating because of how the people react, like the 5 become 1 series of traps in Saw V. When you have 5 people potentially faced with death and see them willing to double-cross each other or sacrifice one of the group just so the rest can progress, only then to see that attitude come back and bite them on the ** at the end, like the circular saw bit at the end of the 5 become 1, when Brit and Mallick realise that the final test was designed with the idea that all 5 were supposed to work together in order make it to that point, that's actually quite brilliant.

I was always a big fan of multi-person traps. Nothing will top the Saw 1 bathroom for me and how Gordon and Adam went from panicking strangers to two people genuinely trying to help each other.
I also like the combat-esque traps, such as the mausoleum in IV and the pound of flesh in VI. Though they go against Jigsaw's philosophy since someone must die, it's interesting to see how two people (people that know each other in the pound of flesh's case) react when they're pitted against each other like that.

I personally liked the traps with multiple people. I mean, a single trap is much more terrifiying, but multiple person traps show how people have to think through things and act together in order to survive, like my favroite trap, The Bathroom!

Single person traps are the best by far.