I have the Fishpond Summit - been using it for two or three years now. It's a good mid-sized sling. Comes with a velcro foam patch for the outside of the bag, and has velcro pile on the front of the strap (so, on your chest ) for another patch if you want one there. Connections points for nippers, foreceps, tippet spool holder, etc are all well-placed. There's a sleeve in the back of the bag that fits a long-handled net, but I use a magnetic net holder on the top of the pack (very similarly located to what Haggis57 posted above), and I find it quite easy to reach and replace the net from my back. It holds enough for a full day outing, and has a good waterbottle pouch on the exterior that doubles as a garbage receptable for me. Also has exterior strap points for a raincoat.
The extra snap connector (for the secondary strap) didn't stay on very well for me, but fishpond mailed me like three extra ones for no charge when I asked them. All in all, I'd buy one again. I hated my first vest (I tend to tangle on stuff hanging on my front), and this was a great solution.