Definitely against the plus and minus system. I got all As and one -A last semester and it wasn't a 4.0 ):
The +/- system is a two-edged sword, but in general I am against it.
I feel that the systems has more disadvantages than advantages. There now can be such a small window in certain classes to get the grade.
The problem is that most people shoot for the lowest possible grade they can get to still get the same letter grade. For example, most people aim to get a 90% in normal 10 point scale courses. These people (myself included) are the ones who feel like they are being penalized by the +/- system.
Minus's definitely hurt, besides you can get an A-(3.7) but not an A+(4.3).