I cannot resist the allure of the Schrodinger puzzle. It's so cool when there are two answers which work equally well. Sometimes one answer is more tortured than the other, but most all of them today are very nice. A prime example of a home run is FISH and FIST, both of which are landed by a hook (a FISH by a fishhook and a FIST by a right hook). Very clever clue for both!
These types of squares are very difficult to pull off, so it's even more impressive that Andrew was able to incorporate so many of them. Thirteen answers are affected, with eight squares needing to work with duality. Just getting one or two to work well is hard enough, so tossing in a huge handful is incredibly impressive.
And given the theme density, I would expect the fill to suffer greatly. Not only does Andrew need to work around the themers BEST THREE / OUT OF FIVE, but he has to place five "coins" throughout the grid. Each of those "coins" requires two answers to be placed (one across, one down), and a set of intersecting across/down answers generally makes for tough constraints. When you have five of them, you're asking for trouble.
As if that wasn't enough, there's the HEADS/TAILS in the center, making the entire puzzle heavily constrained. Sure, there are a few bits like AMBI, SKAT, and OST (all in the NW area), but the grid is remarkably clean. I wondered if Andrew could have gotten rid of the OST and AMI by placing the first coin in the SW corner instead of the NW? That SW corner feels much less constrained and ripe for a "coin," although this would require a different set of dual-working answers than ISH/IST and GUSH/GUST due to length requirements.
And yes, the grid is too segmented for my taste (the entire NW and SE can be sectioned off by adding just one set of black squares, which breaks up the flow of the puzzle), but I'll happily take that sort of thing when the payoff is good enough.
My final reaction: at first I felt like there was almost a little too much going on. What with all the coins and the answer in the middle and the theme answer telling me BEST THREE OF FIVE, I wasn't sure what to look at first. I started to overthink it all, brainstorming how nice it would have been to make it some sort of predictive magic trick, or to tie the central answer to the coins themselves somehow. And then I decided to just sit back and enjoy it.
Neat idea, and a grid executed with obvious care and devotion to clean fill. Much appreciated by this solver!