Somshankar,
I don't want to oversell the 6xx but it is the best headphone outside of the 800s for cello music. I must also explain that I did not hear that until I put it on my tube amp. The tube seems to fill that soundspace and makes it warm without losing the detail. I was listening to Bach Cello Suites No. 1-6 and kept hearing a sound that I thought was a low hum from the tubes. After a while of listening and ruling out the tube I realized that it was actually the cellists breathing. To me, it shines the most when fewer instruments are present because it does tend to lose some of the sound definition during orchestral music especially in the brass section. It will go from beautiful sound separation where you can pick out individual instruments to a blurring of the lines in which you can no longer hear the individualism of each instrument but the tonality of that sound range is still there and full. Now when you have a trio or quartet where the instruments individually own that sound space you wind up in audiovana. You can hear fingers drag along strings, piano foot pedals changing the tone of notes, breath from horn and wood wind players and fullness of voice from a singer. I watched Natalie Cole do her duet of unforgettable with her father and literally cried. I can listen to just about anything with these headphones but will say that to me, these shine in that wonderful space of fewer instruments and precision musicianship. When it comes to EDM, R&B, Rap and even big band where bass plays a huge part of the score, they perform but to me, that is best on my lcd 2 closed because of its deeper and heavier bass presence. Blues, Jazz, classical, cello, guitar, quartet, trio and a Capella are just a few that sound absolutely amazing with the 6xx on a tube amp. I don't know what everyone else's experience has been with these headphones but to me, there is none better to my taste in this realm. It took me some time to tune the tube amp to the sound I like by rolling tubes but once I found the right tubes it was a done deal. As for the difference between them and the jubilee, I can not say because I don't have them, I do however have the 598SE and will say that in comparison, the 598SE does have a bit more lower register presence in both the lows and mids, but it is not as clean or warm to me. Don't get me wrong, they sound great but they seem to lose a step in comparison. If I had to choose between the two, it would boil down to whether or not I am using a tube amp. without it I can see an argument for not getting the 6xx depending on your audio taste, but with it, to me, it does not matter what the taste is, it is a much sweeter and moving sound on the 6xx. So much so that I actually use the 6xx over my 800s for just pure pleasure listening on this tube amp with the music types I listed. The 800s just doesn't give me that same soulfulness that he 6xx does, it has an amazing sound but I normally wind up analyzing more than listening with the 800s. I know that this may not be the case for everyone but for me, that sweet clarity and beauty from the 800s is just not as giving as the 6xx on a tube amp. This was very long but I wanted to make sure that I explained as best I could what I hear especially since I am on a tube amp. Hope this helps, if you have any other questions please just ask and I will get back to you as soon as possible. {EDIT} Forgot to address your question about driving them, I can't really address it because everything I have can drive it just fine. The problem is that everything with one exception is desktop, the only portable I have is the Nano IDSD Black label and even with that, there is no issue pushing it.
Ethan
