Mirrormorph, I love you.
With that out of the way, after playing Mirrormorph more or less exclusively for months, I'm here to give my thoughts:
First thing I learned about Mirrormorph was that Calvin B4L3Y was never really needed. Clicking for a cred for the Mirror trigger was often inferior to drawing, so unless you had no choice but still wanted to trigger Mirror (install, draw, cred) or really needed the cash, Mirrormorph never really wanted for cards. In short, ProCo>Mopus for Corps.
Which leads me to the second thing, flooding. Once you get used to drawing over clicking for the Mirror trigger, you will often find yourself flush with agenda. Gatekeeper helps a bit but it's a reactive card and a proactive option is preferable. Enter Drudge Work. It was a late addition to the deck and boy do I regret that decision. In 95% of my games it has been a godsend, shuffling away vulnerable agenda for cash while triggering Mirror. I've barely had ten games with it and yet I was quickly reminded why I love it when it became a decisive factor in at least two of them. Never change, Drudge Work. Never change.
As for wincons, the obvious wincon is MCA Austerity Policy but do consider Jeeves Model Bioroids as well. As useful as Mirrormorph can be, it can be a bit unwieldy. Jeeves is also unwieldy but it is unwieldy in a way that perfectly complements Mirrormorph. Rare are the turns where you must take 2 of one action and one of another, meaning you can always either fire Jeeves or fire Mirrormorph for that tasty, tasty click. Them combined also gives you access to some stupid combos such as: windmilling a 5/3 or Vitruvius out of hand from a 2 advanced MCAAP with a click to spare (Leela), pushing a 3/2 past a Clot from a 2 advanced MCAAP (purge after the second advance if they summon Clot), and installing and firing another MCAAP after scoring a 4/2. It being a 5 asset also means it has staying power compared to other, squishier assets in HB and its efficiency means that it's a lightning rod for runs despite only being nice rather than necessary in Mirrormorph. It's also possible to sneak a purge or score an installed 4/2 past the runner using Red Level Clearance with it. Great include.
Another wincon option is Hard-Hitting News+BOOM!/High-Profile Target. I've been saying this for months but it still catches people off guard: MCAAP+HHN is a very dangerous threat and you should always be wary of HHN if you see MCAAP. MCAAP messes with the tag math immensely and allows for tag punishment outside of the kill option. My preferred tag punishment is The All-Seeing I but Closed Accounts, Exchange of Information, and Self-Growth Program are all valid options depending on your style.
Mirrormorph's greatest asset is in being able to act from unexpected ranges. I was told once that its best trick is in windmilling 5/3s and, while true, I feel that's selling Mirrormorph short by a lot. Mirrormorph isn't just about scoring that 5/3 from a little further away than expected, it's also about that extra credit in its back pocket for the punish, that extra install or advance you can sneak past for the scoring threat, that extra bit of efficiency that lets you stay one step ahead of the runner at all times. In short, Mirrormorph has more options to blindside the runner with efficiency than just MCAAP so do try it out!
And it only took a bit of Endless Iteration to get there, eh? Eh?