I prefer saw cut. I like the way they close but I have seen some great armor made with some good machine cut rings too. I think it is a matter of preference and it is great that there are options for everyone.
Neat Closures seem more of a breeze to accomplish with Saw Cut jump rings!! (IMO, when rings aren't neatly closed, there is a sense of professionalism that becomes greatly lost on the appearance of the jewelry piece!!)