I would not recommend using OVHs spam filtering as if you have a false positive or need changes adjusted it will take awhile for them to have this accomplished for you. I would suggest looking at Office365 for email hosting.
Both providers have a solid network infrastructure but if you are going to be needing support and do not want to wait days then I would look at other providers.
Admins like to stick with what they know and have used in the past. Price can definitely be a factor for admins on which networking equipment to go with as well.
SolusVM is doing a much better job recently with updates and patches. Hopefully this is a sign they will be releasing all of the features we have been waiting for!
Glad to see everything is working out for you now. We are considering moving our email to Office365 but Mandrill seems to be something we could use as well. Thanks