Hello Art,
I haven't heard any of the ones you are thinking of. However I do have some advise.
First, my experience with any of the BAT "SE" vs.non -"SE", amp or preamp, is that I find the "SE" variants to be more tonally accurate, resolved and articulate of detail, better extended, and more linear in dynamics.
If the sonic difference between the 51se vs.31se is any indication of the differences between the 52se and the 32se, then .... if it were me, it would be worth it to go for the 52se.
Another reason my pick would be the 52se is that down the road you could have it upgraded to the (IMHO remarkable!) REX without having to sell. Also, the fact that the 52se can be upgraded to a REX I think would be a desirable selling point if you ever need to sell the 52se.
Art one of the online magazines gave the 52se a stellar review. If I find it I will send you an email with the link of the review ... ok
Best,
Tom