I'm sorry but v1.5 is just rubbish in my experience. Yes maybe it immunizes agains double the amount of things but it completely messed up my system.
You all know the problemswith the slow loading times so I won't go into that. Also it just wouldn't enable all the protection there was always a few hundred unprotected items with no way of making them protected, sometimes this number got smaller after doing updates but never disappeared.
I've installed 3 versions with the patch and the beta reccommended by the developers, yers the beta cleared up the slowness but f'd up my system in other ways. For instance I had graphics problems with games and other games audio went out of sync after installing it! This is certainley the fault of spybot v1.5 since after removing and cleaning it up each time the sound and video problems disappeared! My system is kept very hygenic so I would know if it's something else.
Now that I've gone back to v1.4 those problems have gone, I'm sure you understand that this can't be a coincidence considering they were gone each time I removed the various versions of v1.5 as well.
I always considered it such a stable program, oh well, might have to give up on spybot now, that's a shame.