It's not all about specs when it comes to purchasing a server, there are a thousand other things to consider.
Take this for example -
http://www.ovh.co.uk/dedicated_servers/superplan_best_of.xml
Looks great, right? And it is, the server is absolutely amazing, the bandwidth provision (15TB @ 100mbit/s) is great and yes overall the server is great. The issue with OVH* is what happens when things go wrong... You'll be left in the dark for quite a while, there is no 24/7 technical support without calling France directly and dealing with a language barrier whilst you talk to a technician, and even then, you have to wait quite a while.
1&1 is virtually the same, perhaps not everyone's experience is identical, but when I had one of their dedicated servers you're left waiting in long queues on the phone, only to be told that they will create a ticket and look into it.
As the saying goes you get what you pay for, and whilst 1&1 may be cheap, their whole business is based on upsale/firesaling as far as I've worked out, and their service (not product) isn't great. This was a couple years ago, maybe they've changed, but I've never seen anything to support that
* OVH actually get a hell of a lot better when you go into their EG/MG range, 1&1's service has been the same at all times from what I read.