Hiya!
Before I say anything else: I'm happy with OVH's services and would gladly recommend them
I've tightened up my mail server today by adding the Spamhaus ZEN BL lookups (
http://www.spamhaus.org ). Looking around at Spamhaus' website I came across their "Top 10 Spam Service Networks" (
http://www.spamhaus.org/statistics/networks.lasso ) and was rather surprised to see "OVH.net" listed at #8.
Perhaps it's a good idea that OVH staff goes through that list, because there are a few outdated listings there but still active in Spamhaus' database. A customer re-using that blacklisted IP might encounter issues when sending legitimate mail - especially with Spamhaus' popularity for Spam BL.
Of course it's difficult to track 50k+ server for spammers, etc. So putting it in that perspective, having a total of 28 listings is not bad - it just "looks" bad at the moment.