The 92126(MM) side were built b4 the 92121(SV) side (early 90s vs late 90s). Price wise, for similar sq-ft, 92121 usually fetch about 10-15% more than the 92126 side. 92121 side have a lot options for larger homes vs 92126 side (~1500-3000sq-ft vs ~1500-2100sq-ft). The dividing line for zip code is Camino Santa Fe (west of it is 92121 and east of it is 92126).
92121 w/ canyon view tend to have larger backyard vs 92126, where you’ll have canyon view but the backyard tend to be smaller. I’d say canyon view probably fetch ~5% more in price.
I can’t really answer who lives here question, but my guess would be people who work around 92121 and don’t want a long commute.
Rent for a 2100sq-ft house is around $2400-2600, depending on season, condition of the house. There’s not a big rental price difference between 92121 and 92126 for similar house.
If I didn’t already recently bought a house and IF a decent house at decent price come up, I would buy there. The key word is IF, since supply in that area is very slim (~8-10 SFR for sale right now), it’s hard to find decent place at a decent price. Both areas goes to MM schools, so school are the same for both. Commute would be slightly better on the 92121 side to LJ and downtown, since it’s closer to the freeway. The west end of 92121 will always be about ~3-5 degrees cooler than the east end of 92126 too.
