Sometimes you can get very good results running a hybrid but I prefer an all tube. I have the LD MT because of the micro tubes, which I have been curious about for some time and nothing else is available. I would prefer to have a tube buffer output. You could do this with a total of 3 tubes very easily although I would do it with four, using one 6111 for each channel as a buffer used by paralleling the two halves, which would double the output current and cut the output impedence.
I don't have the time or the place to do this but I would love to. The LD MT is a nice compromise with good drive and dynamics in a fairly small packageand good looks. The upgrade is to me, the only way to go and I wouldn't even offer the other amp with lesser resistors and one less buffer per channel. I would upgrade the cap that supplies the high voltage to the tube, just out of practice as I feel this is very important dc. What is nice is that the quality of components is very good at this price point and frankly, way above what you would normally get for even more money.
I would also like to purchase a Lunch Box but I would not want an amp restricted to high impedence headphones so the combination of the two amps would be a nice option. If only something like Sennheiser, like my HD650's were going to be used then why not the Lunch Box except I love to tube roll and I don't see much option with the LB. The LD MT does have the option, if you can solder the tubes into the socket of of an 8 pin socket, of using many 6111 type tubes from RCA, Tung-sol, GE, Sylvania and Raytheon from the late 1940's and on. I like this. It also might be interesting to bypass the buffers and use a high output opamp or maybe bypass the opamp.
The amp does possess very good drive and dynamic capabilities as it it. I may try a different duel opamp today but the only one I have doesn't really require buffers, the 8397. Also comparing the MT with detail of my SM LE and IV, I hear no loss of detail, which is nice to know and important to me and the LE gets all the details.