SiteLock is a service that is owned by a company called Endurance International Group, or EIG for short.
You can confirm thishere: https://www.linkedin.com/title/business-development-manager-at-endurance-international-group You notice John C Booker listed as the Sales Manager at SiteLock.
EIG owns dozens of well-known hosting brands, which you can find here: http://researchasahobby.com/full-list-eig-hosting-companies-brands/
If you take any of their hosting brands from that list and search online for complaints, or check their official Twitter feeds, you'll see lots of unhappy customers. Personally I dislike EIG, very much so. Some online research will uncover the many reasons why I don't think they are a very customer-focused company at all.
I have never used SiteLock, but judging on the quality of most of their hosting brands I would probably stay far away from SiteLock.
You can read some SiteLock-specific reviews here: http://sitelock.pissedconsumer.com/
Also, as a side note because I'll never remember where I read it, but there are complaints of SiteLock conducting themselves in some shady ways.
I read a review somewhere a few months ago from a client that was using SiteLock but decided it was too expensive for the budget she had for her small business website. She asked her host (iPage I believe, an EIG brand) to cancel the service. They hassled her a bit, but eventually cancelled the service. Within a day she received an e-mail from her host saying that the site was infected, and that she would need to purchase the more expensive SiteLock911 service to have the site cleaned up. Now I don't really know what happened here, as I wasn't involved, and I really wish I could find that article. But if that story was in fact true, I would be careful giving them my money.