badge :
Well, Windows Defender is free. Why would you need spybot search and destroy? Forget it.
WOAH! windows defender may be free but it doesnt detect ANYTHING!
the teatimer feature is very good, just remember to click "remember this change" if you know that the entry is safe and it wont pop-up so much. I recommend Teatimer because once you remember to click that "remember this change" it will only ever pop up when you are installing something, however if it pops up when your not installing then you know that a malicious piece of code is trying to infect your computer (always remember to ensure that auto update programs are not installing stuff).
its hard to quantify programs like this, they are rated by how much stuff they detect and which ones do the least damage removing those nasty pieces of software.
spybot is very good because it is always being updated to detect new trojans, it doesnt harm your pc and can detect alot of malicious software. Of course no prgram is perfect here at work we run all of these:
Trojan Remover Portable
Spybot Search and Destroy
Adaware
AVAST
and Spyware blaster.
we find that the combination of the programs above pretty much secures all our pcs from 99%(theres always new threats so this value can never be 100%) of threats.
P.S
the reason i state that Windows Defender doesnt detect anything is because im a tech ICT and manage several hundred computers, every computer here has Windows Defender on, yet every few weeks i can garantee i get a complaint from a user saying that strange things are happening, well i take these computers in and run the programs above and can find several cases of malicious software. Windows Defender worked when it first came out, but now it just seems to do nothing.