Goldwater State has has a long and intelligent post about Arizona's Prop. 207:
if 207 passes, the government can't take your home and just give you its cash value if it wouldn't be enough to buy another home. Eminent domain takings will no longer turn homeowners in poor neighborhoods into renters.
The most exciting–and the most controversial–benefit of 207's passage would be its partial-takings clause which requires the government to compensate property owners for regulations such as downzoning (do a search for Emmett McLoughlin to find out why that's a big deal) that take away from the value of their property by directly restricting its use.