i am very new to this and bought a clone dm800se and got it working with the help of this website and its guides. I don't use all the features but it has what i need. I can not compare it to other boxes but from my research , the opinion i got was; if you are going to go clone, go dm800se.
Original Dm800se is over £400...clone 800SE is around £140 . Theres no advantage to be gained from buying an original 800SE a clone with a A8P SIM will run all the latest genuine images. Original DM recievers are very overpriced.
I know you asked about the Dreambox, but I think you should look at Technomate TM Twin, excellent box, London based company with 0208 technical support number and you can pick one up for around £300 with a 500gb HD.
its chinese new year at the moment so there holiday time .
this means all deliveries will take longer than normal as they will not despatch orders until back from there hols like our xmas new year shutdown