I picked up a new "Standard" (old school wood stocks, fixed sights, blued finish, ambi safety) from the local Gander Mountain last year as a birthday gift to myself...I love it. I don't like the adjustable sight models as they look very uncomfortable to carry IWB, and I carry my BHP. Don't let the grips determine what you buy; you can always replace them. Brownells is set to get a shipment of Navidrex BHP grips, you should be able to find a set of Craig Spegel grips online, Pachmayr's wraparound grips are actually very comfortable on a BHP...there's plenty of grip makers, so don't limit yourself on that.
The only real differences between the Mk3 and the Standard is the finish (I prefer the blued one, but YMMV) and the grips. You can get either with the adjustable, or the fixed, sights. I'm %99 sure the GM I went to had a Mk3 with adjustable sights in it's display case as well, but I could be mis-remembering.
My wants, in order of preference/care, were that it have fixed sights first off, and then I'd prefer the gun to be blued vs epoxy (not that it really matters but I liked blued guns better; they look nicer to me
). Fortunately they had a classic model with fixed sights in stock, so I got that. Had they only had a Mk3 with the epoxy finish in stock with fixed sights...I would have gotten that instead.
You can't go wrong with either model.
All of which reminds me, I need to get in my pre-order of grips from Brownells