Last year I had narrowed it down to Aric or LTA, and read everything I could find. After comparing some DACs, I realized my personal preferences leaned a little more toward detail and speed which, based on my reading, I figured the ZOTL circuit would have the edge on a more traditional tube pre. The MZ3 is also a headphone amp and an integrated which was a bonus. This got me started down the headphone rabbit hole, but I've decided I like it much better as a pre than an integrated. And if I'm being honest, having more functions on the remote (even if it is a cheesy Apple remote), was a plus as well. With the right tubes I think either can be incredible, but my gut tells me I gave up a little of what you're looking for to get what I valued more.
Search reviews by Terry London for the Motherlode and the LTA preamp. I used those and a bunch of others to come up with a general characterization of what the next level down models that were in my budget would do. If I ever need another preamp I'll start my search with Aric because I'm always going to wonder what I missed out on no matter how happy I am with the MZ3 right now. I'll probably be looking at one of his SET amps first though. Send him an email if you have questions.