It is the site we are using right now xD
YOU ARE USING IT AND LOOKING AT THE REVIEWS FOR IT!
It is safe! You are using it right now!
I've had Norton for many years. I've had Advanced System Optimizer 3 (ASO) [a Systweak.com Product] for 5 years. I had ASO 2 about 8 or 9 years ago and dumped it, because it was 'too quick' to find minor malware (by which I mean it 'appeared' to be smoke and mirrors).
I have used Version 3 for 5 years, and it's the BEST software I have, in that it is actually better and quicker than Norton to find the minor stuff. (that is proven, by the fact that on a number of occasions whilst I had System Protector, one function of the ASO suite, running all the time, and it used to pick up the minor stuff 'before' Norton found it. I KNOW this, because I would look at the Norton quarantine every so often, and find that it had extracted the malware not from my general system, but from ASO's QUARANT...