@vitop Good question! As for why the DI SE over the Ulfberth or Mini Ulf I don't have technical reasons.
Other than @333jeffery 's feedback on his Ulfs and @teajay 's take on them there isn't much out there and nothing on the 'Minis' or the SEs.
The Ulfs would work in my current room, but would also overwhelm the aesthetics. As long as I listened at lower and moderate volumes they would be great, but I wouldn't be able to let them truly loose in this room. I didn't discuss the Ulf's with my wife because I just don't want to do that to the room for her sake. If we were ever to bring 2Ch into our formal family room then the Ulfs would be a perfect fit there.
As for why the SEs over the 'Minis', it came down to a known quantity with performance I'm already very satisfied with. Upgraded parts for speakers have generally correlated strongly with higher performance. The SEs also save me some cash and since I'm going to add a tubed amp into the mix, every bit of savings helps.