Version 1.6.x and prior releases were excellent. In recent years, the product decline to the bottom of the pack. No longer is it recommended and the free version lacks the Bitdefender engine. If you are using Windows 7 SP1 or higher, then no please do not consider using Spybot Search and Destroy.
I recommend using Malwarebytes Anti-Malware Free and / or ESET Online Scanner for on-demand scanning.