BAT VK-3i vs. VK-3ix

Has anybody compared these two? Is there a substantial difference? Thanks.
From what I understand, the old 3i was based on the same topology as the 5 and 5i. The 3iX is based more on the topology of the 51SE and 31SE. I talked to Victor at CES, and he feels that it is a significant upgrade-- especially given the availability of an SE version.
Interesting. I am not enamoured of the SE series ... I find the super-tube to be harsh and clinical sounding. Also, there's no opportunity to tube roll. I spoke to BAT today and they said the 3iX is an upgrade over the 3i IF I go for the BAT-PAK and/or other options ... they very enthusiastic about it in the SE version. I will try to audition a unit, but don't feel in such a rush to change at this point. Thanks for your help.
I have this gut feeling that I will like the 3iX SE more than the 31 SE or the 51 SE. It just strikes me as perhaps being the ideal preamp for me...

I just need to get to a dealer and listen to them. Unfortunately, I can only do that when I travel, as there are no dealers anywhere near me, but we'll see.