I'm not sure about the DDOS protection (never had this problem yet) but for dedicated I have tried a few and Softlayer is way ahead of anything I have tried.
In particular, their customer support is outstanding so that might be a big factor based on your concerns.
I guess the OP had some issues with DDOS atteck in the past and that's why he wants to protect their dedi against this problem now.
Dare say very few companies provide dedis with DDOS protection and if Santrex.net guarantees this services, stick to them. I have read many positive reviews about their activity in the forums and think you may try them.
I think that any web host must offer that. But each company have own concern of the development and own solutions. For the dedicated server with your request I think that you can also (in additional to named here servers) have a look at Globaltap.com, Exmasters.com or ServerBeach.com. They are well established dedicated server hosts and they must have these solutions included and that must be comfortable for you
I can recommend gazzin.com. They have recently launched dedicated servers providing and thus have to be reliable. They provided DDOS protection. Prices are average.
If Santrex.net provides DDOS protected dedi ... hm it's very rarely when the companies provide this feature. They also allow adult, IRC and torrent on dedis. And prices are not very high. And the location is different.