Musical Design - D150B & SP2B Opinions

I am interested in how this amp and pre-amp compare to other designs incorporating solid state amps and tube pre amps or how they, as individual pieces, compare to other manufacturer's equipment?
Lots of luck John I posted info for the amp,and so far have received zero response. Jeffs Sound Values had a used D 150B for sale at $750.00. Was interested but couldnt get a response here.
Sorry John for my slow response. I have both units and am extremely satisfied. I feel that they will perform at a level of performance far exceeding their price points. They have been very reliable and sound great day after day. Best kept secret in audio. I would compare them with equipment of any price. Good luck.
I absolutely love my Musical Design D150B amp (s).   Actually I had purchased my first one 3 years ago ...but had my recordist buddy who has Quad 989s, the big black ones...he picked them up for me - ( BIG MISTAKE !! ).  He kept talking about how transparent his recordings sounded, how sweet, neutral, powerful, stable etc. the amp sounded ON HIS QUADs...that I finally gave in and let him keep them. 
It took me about 2 years to come across another D150Bht it up for sale....bought it and it has been the "reference in my system since.  Sounds great even without a preamp ( I used a Bel Canto 2.5 dac with remote control for volume control.
Wonder what it ould sound like with a Hillig preamp.
typo in previous note...NOT D150Bht...correct is D150B !
Both are nice products. I have owned both.
The SP-2b comes up for sale occasionally in the $400 - 500 range. Well worth considering.