I have owned the LS-100 as well as other 6SN7 based preamplifiers, and while I have not owned or heard the 36.5, I have owned another 6H30 based preamplifier and I have to say that I prefer 6SN7 preamps to 6H30 preamps in a general sense.
The 6SN7 preamp will have more tone, warmth and body then the 6H30 preamp, while the 6H30 preamp will be remarkable in its clarity.
But a lot of this really depends on synergy with the rest of your system and your personal preferences. Also, if you're looking for a balanced preamp, the LS 36.5 is truly balanced versus the LS-100 which has XLR outputs only for convenience.
What does the rest of your system look like?
The 6SN7 preamp will have more tone, warmth and body then the 6H30 preamp, while the 6H30 preamp will be remarkable in its clarity.
But a lot of this really depends on synergy with the rest of your system and your personal preferences. Also, if you're looking for a balanced preamp, the LS 36.5 is truly balanced versus the LS-100 which has XLR outputs only for convenience.
What does the rest of your system look like?