I have found them to be good when it comes to hardware issues - which I guess is their main area of expertise - but rather shoddy in other areas.
eg, as a plesk reseller, they are supposed to provide plesk support but, ime, it has been a case little more than regurgitating the plesk manual at me.
Also poor customer service - they seem to have a "this is the way it is and if you don't like it, bugger off - ppl are queueing up to sign with us".
But, as I said at the top, their actual support for their hardware is good.
Also, pricewise, I have found them to be pretty good actually for the sort of servers I want - their P2800S offering for example I cannot find equivalent for about the same money at any other reliable DC, bearing in mind the 40GB NAS you get with that server too. Granted, the setup fees are a killer though
Every DC has it's fans and it's detractors - I would say, if you are happy with them then stick with em rather than trying to save a few $$ - the next DC might not be so good...