I currently live in Eagle Idaho after living in both Southern (Riverside) and Northern (Sacramento) CA.
The Boise area is nice. People are generally friendly and aren't idiots on the road. Often times they will let you pull out of a driveway, holding up traffic. I've never observed any anti-California sentiment with the people that I've interacted with - either in Boise or any of the smaller towns. In terms of the weather, there are 4 distinct seasons. January is a bit grey because of an inversion where the clouds settle into the valley, but drive up into the hills and you're in the sunshine. Summers are warm and generally have a couple of weeks of 100+ degree days in July and August. A large snowstorm will drop 3" in the valley and generally melt within 24 hours. Ice can sometimes stick around on the roads for a while, but you learn to deal with it. 4-wheel drive vehicles are not required.
Cost of living is significantly less than any part of California. Eagle is a nice area and a 3000 square foot house in a nice area, near the green belt (great exercise, biking path) will run you between 250k - 400k, depending on the ammenities and age of the house. Houses tend to run a bit larger here than CA I've noticed as a general rule. Things like gas, electricity and insurance generally run a little cheaper than California as well.
One of the big advantages of Boise is the ability to go outdoors most of the year. I've already mentioned the greenbelt, but there are multiple farmers markets, skiing during the winter 30 minutes from downtown, hunting/hiking/camping/ATVing and many other activities.
Some things that I didn't expect coming from CA? Many things either aren't open on Sunday or close early. Liberal views are rare in the state, more common in Boise. College education isn't pushed by many parents here in Idaho - it's available, but many teens and twenty-somethings don't take advantage of it. Unemployment is low, but many of the jobs that are out there right now are low wage, service sector jobs. Higher paying jobs are out there, but harder to find because of a smaller population base and more of an emphasis on farming/ranching in the state. You'll also likely become a Boise State (football) fan. It's hard not to get caught up in the excitement, go to occasional games and root for a local team that is doing well and getting better.