Well, haven't put all three through their paces, but I ordered a few different ones from Amazon (all ~$9 or so).
Have used the Diztronic 3 for nearly a week. I think it's a great case. The cut outs are perfectly located. It's a touch slick but certainly grippier than a naked phone. It's a little on the boring side appearance wise, but no big deal. And of the three, it seems to be the sturdiest.
On top of that, I got this one:
http://www.amazon.com/Teal-Androidified-Samsung-SCH-i515-Packaging/dp/B0060PBZ8A/ref=pd_sim_cps_10
Got it purely for aesthetic reasons, thought it was pretty cool! First thing, it's quite glossy and very slip resistent which is great. Seems to be probably the flimsiest in material of the three. Main issue is the volume rocker is not cut out. Had to be done pronto as any slight pressure on the sides caused the volume to go ALL the way down. I cut out a good swath for it and all seems to be well.
Last was this one:
Amazon.com: SAMSUNG GALAXY NEXUS BLACK TPU GEL SKIN CASE, IN QUBITS RETAIL PACKAGING: Electronics
I've only put it on but haven't spent much time with it. Also doesn't have cutouts for the volume rocker but it's not as bad with depressing them without without wanting to. I like the grippy feel is has on the sides. The back is only partially slick.
All and all, I was just looking for something simple as I went 2 years with my Droid with barely a scratch on the outside and never a case. Would recommend all three to anyone looking for something simple, cheap but doesn't need the protection of an Otterbox.