Hi Stereodad; I have used the SF Line 2 for about 3 years and consider it excellent. I haven't heard the new SE version, but it uses a set of 6 Valvo tubes, and I suspect those tubes are the main reason for the sonic differences in the SE.
I say this because I tried the Valvo's in my std. Line 2, and there was quite a difference. The Valvos are much more sweet, euphonic, and "tubey" sounding. It was a sound that I didn't care for. I preferred the the much more neutral Sovtek tubes, but many like the Valvo sound.
I have also tried other "exotic" tube sets including one that had a pair of Siemens 7308s and 4 6LN7s-- didn't like that either. But I would emphasize that whether or not you would like the Valvos is such a personal thing that the only way you could tell is to actually listen to it yourself, preferrably in your own system. I know this is kind of the "stock" answer to such questions, but in high end audio it really is true.
Personally, I would like to try the new SE version Line 2 with Sovtek tubes. Good Hunting. Craig.