After climbing packs, no item of gear has obsessed me more than boots, and in fact they are more critical by far. The first pieces of critical mountaineering kit I owned were a pair of double alpine boots, the Asolo 101s, a pair of Galibier Superguides for summer mountaineering and a beautiful Marmot winter sleeping bag, the much-loved Gopher. I still have the latter (as well as some Julbo glacier glasses) but I sold the former Asolos, which were yellowed with age by then. The Superguides were still to be seen on my long-time climbing partners feet until very recently when he started a long-term loan of another friend's LaSportival Nepal Tops, but I think they get broken out when he takes unwitting victims for a day of ice cragging. These items were laid in before I graduated high school, so early 1980s.
Boots have changed dramatically and for the better. Where the Superguides were over 7 pounds for the pair in my size 46 (US 12), now much better boots are closing in on half that, with the Nepal Top topping 4 pounds for the pair.
I have found that my feet change over time, and that generally dictates which boots I prefer. I was in the above-mentioned Asolos and Super Gs for years, but sometime (90s?) I got a pair of Scarpa Assaults, which were like Super G's on steroids. I love them for their ability to climb ice, and mixed, but they were heavy and a bit of a bear on the hike in. I also had some trouble with frost nipped toes, generally not an issue for me, and I think it was in part because they were quite stiff (good for vertical ice) and high, and mostly because they were single boots.
After that I found that every decade or so my rock climbing shoes would switch from fitting in LaSportiva's last to Scarpa. I have no idea why that is, but I have a low volume, low arch foot, with a bit of a wide forefoot, and each last (shape the boot is made on) is different. When the Assaults became too assaulting, I moved to some early generation LaSportiva Baturas (before the Boa was added I think) and they were very good. I think that I sold them, don't recall, but more lately have had 2 generations of the Scarpa Phantom Tech:
Outdoor Gear Lab Phantom Tech review
The first generation was not perfect, with slippery dyneema-like laces which were barely long enough and had to be double knotted to keep tied (most of the time,) and a bit heavier than ideal. The more recent version is amazing, lighter, warmer, and without the lace issue. I would even wear them for summer alpine outings if we had those and I did not own another pair of Scarpa singles (the Rebel?). These were sold to me by the wily Rich Gottlieb at Rock and Snow. He in his defense had sold me a barely used pair of Technica hiking boots I loved for years (and got for <$100.) When they finally blew, I was looking for hiking boots, but he got me into the Scarpas, and they have served well, including my teen who has used them even in pretty chilly temps until this year. But the Phantom series (there is a 6000 and an 8000) are the way to go, for me, if you want an integrated gaiter (pretty standard and key these days) on a light, technical and generally killer boot.
My son recently won on Instragram a beautiful pair of LaSportiva boots, the G5 Evo, and I expect those to be extremely effective, and his foot likes the LaSportiva last, but no trial runs as yet.
Some great links to further research the topic:
Outdoor Gear Lab 2024 Mountaineering Boots
Trailspace 2024 Mountain Boot Reviews