I have owned several Millies and a mini-SERE. While I can't do a head to head comparison for you since I haven't owned the larger SERE, I can vouch for Al Mar's overall F&F and their attention to their blade beveling and O-O-B sharpness. I really liked the mini-S. It had a very smooth action, positive lockup, and no b/p in any direction.
My mini-S carried very well in RFP or IWB with it's low-rider clip. The SEREs are TU, the Millies are TD, if that makes any difference. Al-Mar does VG10 very well and it's one of my fav folder steels, so I didn't have any concern about the performance of the blade material. Both knives are open construction so they're pretty easy to keep clean.
For me, the knives worked equally well and I had complete confidence in either one I was carrying and using at the time. The choice of which to keep and carry came down to personal preferences. I like the Military's blade shape a bit better than either of the SEREs because of the long curve to the edge and I like Spyderco's FG S30V better than just about anything else I've ever found including VG10.
Good luck with your decision. Somebody'll come along shortly and give you an apples-to-apples comparison between the big SERE and the Millie.