The Proton-M's initial thrust-to-weight ratio is about 1.5, which is somewhat high. Falcon 9 is about 1.2, and Delta IV Heavy is about 1.25, for comparison. And of course since the Earth subtracts a constant 1, that means the Proton-M's initial vertical acceleration is 2-2.5 times higher than those examples.

I'm not sure why it's different. Higher TWR is more efficient (to a point), but it also means there's potentially additional capacity to be had by carrying more fuel. Maybe it has something to do with Proton's origins as a gigantic ICBM, although that was a long time ago.

On a tangent, reading the Wikipedia entry for Proton-M, there have been 117 total launches and 11 failures. That's a mildly terrifying failure rate!

It occurred to me that with the Russians launching out of central Asia, there must be some chunk of land to the east of there with a ton of rockets falling on it, since even with a successful launch the first stages are just dropped. I couldn't find much info on that, but there are some really cool pictures here:

http://www.eurasianet.org/departments/culture/articles/eav04...

And some history here, but no rocket pictures:

http://www.russianspaceweb.com/baikonur_downrange.html