I work out in the field year-round here in Colo and abuse boots. You are definitely on the right track with an all leather boot. They will outlast synthetic boots by a long shot. Synthetics generally have quite a few seams compared to all leather boots. The fewer seams in a boot the better. From my experience the seams are where boots tend to leak and also fall apart first.
The only draw-backs to all leather is weight and stiffness. I stay in pretty good shape so it's worth it to me to wear a boot that may be a little more weight but lasts a lot longer. My feet may sweat a tad more in all leather but for the most part not bad.
It's a good idea to treat leather with waterproofing if you are going to be in snow and wet weather. It's not only good for the leather but also makes them even that much more waterproof.
You can't go wrong with Crispi. Some of their older models that recently changed slightly have great deals. Usually around $100 off which is a bargain! If you do a web search you can find them. It may be tricky finding your size but there are a number of web stores that may have them. You may also be able to find some coupon codes for additional savings.
In regard to Crispi all leather boots here's a short list: Valdres, Dakotas, Briskdals, and Nevadas. A work buddy has the Valdres and really likes them. They are the lightest Crispi all leather available. The others are fairly close in weight. I have the Dakotas and also Wyo's....and like both. I know a lot of guys like the synthetic Summits...but I'm not sure if they are as rugged and the waterproofing lasts as long.
I've also had great luck with Lowas. I have a pair of Lowa Tibets that are fantastic boots. They are taller and heavier so I only use them in snow. I also have a pair of Caminos that are lighter and are a great all leather boot.
