I started with Race Face Chesters because I had zero experience and didn't want to spend much money on my first guess. I ended up putting about 5000 miles on them with no complaints. Chesters are a bit thick, made of plastic, are totally flat, and have pins (screws) that leave a scar.
About 3 months ago I decided to try concave, thin, alumin(i)um. Oneup products seemed to have good reviews, so that's what I bought. I am not a highly skilled, sensitive, sophisticated rider, but I can easily feel the difference between the thick plastic flats and the alumin(i)um concave, and I like the concaves better. The grip on the shoe seems to come partly from the shape and partly from the pins, whereas the Chester's grip was all from the (vicious!) pins.
So you want opinions? Mine is to look at thin, concave alumin(i)um pedals that have a good reputation for longevity and are rebuildable if the bearing need to be refreshed.
Edit: Spell check thought I wanted to say that the Chester pedals were a thick and syrupy liquid (viscous), whereas in fact they are mean-spirited (vicious).