BAT REX and VK 52se above the VK 51se

There is a record number of BAT VK51se preamp listed for sale at Agon, I cannot recall ever seeing so many available at the same time and I guess most are being upgraded to the REX and 52se.
I would like hear from members who have compared these units and how much more superior are the REX and 52se over the older 51se.
There are no BAT dealers around my location to make my own comparisions but I do own a 51se and I am now bugged about upgrading also.
Thank you, Terry.
My dealer told me the 52se wasn't a huge upgrade for the $$'s over the 51se. I've heard the REX. Oh my, that's one hell of a preamp. It floored me.

Huge step up over a 51se.
As the saying goes - you can't get there from here (51SE to REX), hence the log jam of 51SE's for sale. The upgrade path ended at the 51SE. Most will need to start or 'upgrade' with/to the 52SE, then add the REX upgrade, as funds allow, unless pockets are quite deep.
The 52SE has a second generation Super-Pak increasing capacitance even further over the 51SE, adding further "textural liquidity and coherence" as the BAT website states. An improvement, yes, however the 52SE seems to have been created to be the launching pad toward the REX, BAT's statement piece. Unless you plan on eventually going for the REX, your current 51SE may suit you fine for quite some time, at least until used 52SE's start showing up for sale.
Hello Terry,

Being a previous owner of the 51se and now a owner of Bat's best pre-amp to date the REX, I can tell there is not one area of performance that compares. IMO the REX is really that good! I'm just absolutley floored by it each time I turn my system on and listen to music. I haven't heard the 52se.

Good luck,