I also have been listening to the MHDT Havana for about six weeks. I don't have the Paradisea but I do have both a Benchmark DAC 1 and a Lynx Studio 2B. I'll chime in with some observations.
First, I swapped out the stock tube with one recommended on the MHDT web site, and this has made somewhat of a difference in detail and overall tonal balance. I did a lot of listening back and forth between the Havana and the Benchmark. While the Benchmark didn't seem to care much about what input is being used, the Havana sounds slightly cleaner using the coax input over the USB and optical inputs. I can also hear differences between sources using the Havana even when driving the same coax input on the DAC, I suppose this is because the Havana does not resample and reclock the input stream as the Benchmark does.
Regarding a comparison between the Benchmark and the Havana, the Havana is very nearly as detailed as the Benchmark, has more midbass presence (or midbass thickness, depending on your point of view), and more midrange presence. While I can't pick out background noise with the Havana, music still appears to emerge from a quieter background when listening through the Benchmark, although for me this difference disappears when using a source such as the M-Audio Delta 410 card in my PC. I think this is again probably due to the Benchmark being less sensitive to jitter.
It is worth mentioning that in the crude measurements I took of both DACs, the Benchmark measures far better than the Havana. Hence I think the Benchmark would excel at it stated purpose, which is primarily a DAC for monitoring while mixing and mastering.
I've briefly described some of the qualitative differences I hear in the two DACs, but haven't yet described which DAC I prefer and why. In my opinion, the Havana is a far more satisfying DAC when sitting back and listening to music. The first reason is that the added presence in the midrange sounds closer to what I hear in live venues. Both percussion instruments and stringed instruments sound like real instruments in space rather than being thin and wispy. The second reason has to do with timing, and is harder to describe. In comparison to the Havana, the Benchmark seems to homogenize subtle timing details and dynamic inflections to the point that they are not noticeable. The Havana reproduces such subtle details extremely well. I am a drummer, and when I listen to excellent percussionists through the Havana, I can hear the sticking so well that I can see, in my mind, the type of sticking that the drummer must be doing in the performance. I can't pick out the same timing and dynamic details when listening through the Benchmark. I think it is these details that allow me to easily get into the music and the groove when listening to the Havana. When listening via the Benchmark, I tend to focus on the sounds, but not get into the music.
