Used tube preamps, Cary, AR, Aesthetix, Wells...........or?

Having searched over the last year or so for a different preamp, I have been attracted to the Cary SLP 98 more times than not but I know it has many different incarnations and this seems to be important. The one I put an offer on is 8 years old and no upgrades are known. No real idea how this compares with others. The deal is by no means a lock. They have plenty of others that I would consider.

I have also found an AR Reference Mk II. It is 10 years old so not sure if that is good or bad but I'm sure it would be one that I would enjoy. It has a choice of xlr and rca for every connection. Only one I know of like this, at least in my searches. It is also designed to drive two amps, so is the Cary but the Cary is only set up this way with rca connections. I have never used balanced circuitry even though I've had it as an option. Most of what I've read says that you gain 6 db in gain. Is that the only advantage or is that even an advantage? I for one, do not know.

I have also found Aesthetix, both Rhea and Calypso. The Rhea is more in my price range but used, either is a possibility. They get mentioned here and there. Not sure what to think.

Another find is a Wells Audio Commander Level 2 Class? 2. No idea on these. Not heard anyone speak on them. 

Yet another has been the Dodd, battery powered unit. Haven't heard much but the ones who have them, say their search is over. Interesting. Happy to hear from anyone with any experience on these or others. I know there are tons to choose from but many are difficult to find as well. 

I bought several different preamps that were supposed to be "bargain finds" but none lived up to the one I'm trying to replace. If I'd been smart, I would have been more patient and put all my eggs in one basket instead of fooling around with all the others. It has been an interesting journey, just the same and I now have several pieces to sell or trade. Not necessarily a good thing but as I say, it's been an interesting journey and I have more to go. Thanks for any and all input.

Bill