Deep Freeze: Decent program, but it's more for public access PC's/Lab PC's. A bit more expensive then some of their alternatives but they are the original restore utility.
Shadow Defender: I like it but it's not really snapshot software, more like sandbox software.
Rollback RX: Personally prefer this for my own personal use. Good performance speeds, company (Horizon DataSys) touts it as a 'all-in-one' solution which it's not but still overall a good product.
I use Rollback on my home PC's and at work we use Drive Vaccine. I think these programs serve a purpose, just don't buy into the hype that they'll fix every issue. You'll still want to run regular backups with your disk imager but at least for recovery if you can use a snapshot program it's faster and easier which is nice.