Just grabbed mine out of my Fatboy.
Handle length - 5 inches
Depth is about an inch the front part of the choil is about 1 1/16 with the blade out. With the blade closed, overall depth is in the area of 1 1/4 inches.
Width is about 1/2 inch.
Sorry I couldn't be closer - just using my desk ruler
As an aside - it has the phospor bronze washers. The thumbstud is also reversable for us lefties or strong lefties, but the indent on the G-10 is not as shallow. I had to increase the indent a bit to make it easier, but only on the G-10 - I didn't want to touch the liner. It's also flat ground/AUS8

I'm one that doesn't mind AUS8 - it sharpens up easily and quickly and covers my needs quite well - but I'm not overly hard on my stuff either
As Mr. Wilson mentioned, it is a bit slippery - I have very dry hands and our climate here tends to be on the dry side, so this may be an issue to some. A simple comparison point - it's closer to the feel of a CRKT - M16 that has the gray aluminum handle (I have the M16-03K/EDC), and compared to a SERE 2K, its actually quite a bit smoother. This does require a bit more concerted effort to open and not good if you need it in a hurry. The way the choil is set up pretty well forces you to put your thumb on the thumb ramp when you make a regular cut. If you have slightly larger hands, it's going to make the handle roughly an inch shorter, so it could tougher to get a "fistful" of knife like on the SERE 2K. It definitely does feel smaller with goves one - I was using it for gardening with my GLC gloves which are quite tight fitting, and it felt a lot smaller than my SERE - still worked OK for me, though.
Interestingly, the RAT 1 handle is actually about a 1/2 inch longer (give or take

) than the SERE 2K handle now that I'm comparing the two in front of me. BUT the choil is also deep enough that if you are going to be poking or poking/prying, there's not that much chance of your hand slipping on to the blade either. When I first opened the knife after I got it, the first thing I did notice, was that the top edge of the blade ramped up to a point higher than the handle - most folders tend to follow the handle in a straight line - the back part where the thumb ramp is rises up instead of being flat. I haven't used mine all that much, but what I did notice, was that when I make a cut, I don't need as much angle when I put my thumb on the ramp (I hope that makes sense.....).
Bottom line - pick one up and touch/feel/fondle if you can. It ran about $100 CDN up here and for me, it represented an excellent value for the dollar. I couldnt' bring myself to beating up my SERE 2K so I bought this one to use as one of my larger blade beaters - it cost me roughly 1/3 of the SERE 2K.
Edited to add - sorry for the extra here - on the handle width - just grabbed my Endura 4 and the RAT 1 is maybe 1/16 of an inch wider (just eyeballing). Also noticed that my Spydies have that ramp to accomodate the Spydie hole - maybe that's why I like my Spydies so much.
Hope this helps - gord