
The first thing to say is that the fit of boots is more important than anything else, including weight and my recommendations! All the big name boot companies make suitable models. I'd suggest finding a store with a good selection of boots and staff trained in boot fitting and spending a few hours trying different models.
Year round hill boots come into the 3 or 3-4 season category and are a little stiffer with firmer uppers than 2-3 season boots. Weights tend to be in the 1500-1800kg range for a men's size 9. Lighter weight boots are suitable for scrambling and can be worn all year round, even with crampons on easy terrain for short periods. If you plan on wearing crampons on more difficult and steep terrain then heavier, stiffer boots are better. Any boot will be a compromise between comfort and coolness for summer walking and stiffness, warmth and waterproofness for winter use, especially on snow and ice.
In the medium weight category the Scarpa SL is an excellent boot that comes in two width fittings, unlike most boots. They don't have a waterproof membrane lining, which I find too hot in summer. Last winter I tried and liked the Berghaus GR20 (1686 grams), which comes with or without a membrane, though it's a little narrow for my feet.
I also like the new Brasher Trailmasters (1524 grams), though these do have a membrane. Overall my own choice for a year round boot would be the Scarpa SL in the wide fit. However I don't wear boots (except for testing) between May and the first snows of winter, preferring trail shoes or sandals (I've just crossed the Scottish Highlands on the TGO Challenge in a pair of Brasher Rapid shoes and last summer I walked the Southern Upland Way in sandals). I find any boots too warm in the summer. The coolest I've tried are leather ones without waterproof linings like the SLs.