I have had a very poor experience with ServerMania. I run a VOIP application in a small cluster of machines sprinkled around North and South America; basically, it's a multi-headed Asterisk-based PBX. I had a dedicated VM server in their New York facility. Then they put in supposedly DDoS protection, and we started getting complaints from our customers about poor quality, inability to register their phones, a host of stuff. 99% of the times, everything still worked fine.
However, people are so used to 100% reliability from their phones, 99% is too poor. For me, DDoS doesn't help that much. Our IPs are only published to our clients and they are businesses. I suppose someone might eventually try to hold us hostage or something, but it has never been a problem.
So anyway, I went and got a VM in their Los Angeles facility. I added it to my cluster and immediately, they started yelling at me for abusive use of their CPU, I was using too much of it. The only thing I had installed was a copy of mySQL and Asterisk, and it had zero load on it. A few days later, they sent out an email saying that they were going to rebuild the RAID array. Obviously, one of the disks had failed. The reason why my VM was taking so much CPU, even with zero load is because anything that it ever tried to do, the failing disk would take forever to respond, and that would lock up all threads on disk reads, basically driving the load average through the roof.
However, I didn't want to stay and argue the point. I had paid a year in advance, and I gave the VM to some friends. One of the few things a small VM would be good for would be to run a chat server. The AUP for their network does not allow open proxies, so if you connect to their network, they will scan your IP for open ports. ServerMania's AUP does not prohibit such scanning (at least, as of the writing of this review.) At 11pm yesterday, they decided that the chat server was going on a rampage and making DoS attacks against the chatters connecting to it, and on that basis turned off the machine. It's difficult to see how a chat server is "attacking" clients that successfully connect to it.
I was woken by my friends at 11:30pm, I filed a ticket explaining this, and 12 hours later, they haven't even bothered to respond, let alone turn the machine back on or at least tell me that we have to turn off the port-scanning. Dead silence. That pretty much takes the cake for me.
In conclusion, I think their real problem is that they really don't understand what a DoS or a DDoS is, both from a attacker or the attacked's perspective. This serious lack of technical understanding is what scares me away from the idea of ever having a server with them again. Aside from that is the fact that in a professional environment, you cannot leave tickets unanswered for half a day, not when a server is completely down.
Interestingly, I had a similar experience with DDoS with SecuredServer / PhoenixNap. Somewhere in the middle of my period with them, they got DDoS protection. When they saw my problems, it felt like they went in crusade mode to keep me as a customer. I received a call from a Director of something to apologize for having had to wait 4 hours for a response to a ticket, and whatever it was, they fixed it. It's my most stable server, and so far have received zero connection complaints from any customer (if their internet is working - doesn't always happen.)