I just picked up a Benchmade 520SBT Pre-production model at a local gun shop and though I'd share my initial impressions.
The 3.42" long, 0.13" thick 154CM blade is razor sharp. The handle is 4.87" in length and consists of aluminum scales over steel liners. Blade to handle ratio on this knife may not be the best in the world, but it's not that bad either. Folks with large hands will find the grip quite comfortable. For those familiar with Benchmade auto knives like the AFO, Auto Stryker and such, the handle on the 520 has a sort of grippy feel to it because of the bead blasting process. That combined with the texture on the scales provides a solid grip in wet or dry hands. The removable pocketclip is set up for tip up left or right hand carry and does fit rather tight against the aluminum handle, but if you're an active individual, it is less likely to slide out of your pocket.
At the shop I visited, the only model available was the BM520SBT and I typically stay away from black coated combo edge knives, but after handling the knife I just had to have it. I was that impressed with it. After seeing all the little "gent" knives being released by Benchmade, it's refreshing to see a large and solid tactical/working folder back in their lineup.