5 UARTs. £20? Somewhere between an F405, and F722 (It actually has more storage than the F series, just not quite as quick). 405’s are pretty fine, so £20 for an FC? Who’s going to try it out.
Mads has a video here, speed it up as he only says how interesting it is for the first 5 mins
I’ve had one in my Baby Ape since first build 
So guess you can use the official 4.5 BF now. Guess had one of those pre-release/custom versions of it for a while, like I did on a whoop with an SPI based ELRS!
Just used the stock firmware it came with
Not that I’ve flown it so it hardly matters 
I’m actually kinda excited by this, so I’m totally up for it.
Performance-wise, I’d still manage very happily with F405, but I think AT32 is probably only the second example I can recall of parts getting cheaper!
and that is only a good thing…
when I first started FPV you could pick up a decent flight stack for under £40 these days you’re lucky if you can one under £100 
From the “shopping list” for my first build:
Airbot Omnibus F4 Nano V6 - £23.69
Airbot Ori 4in1 mini ESC 25A - £29.95
And not forgetting…
8 Pin JST-SH Omnibus to 4in1 ESC Cable £0.94!
So not quite under £40 (I wuz robbed!) but a long way short of current prices!
The Speedybee F405 V3 is around £55, which isn’t too bad these days (don’t use 411’s anymore anyone unless you have to, or on a whoop!)
I believe they coming out with AT32 ESCs soon (unless there already are some), so hopefully we see more decent priced full stacks soon too. I dunno if £55 for a full stack is reasonable or not… I’ve paid it before, so…
I have one of these too replace the mamba that I bricked seem ok…
NeutronRC AT32F435 Mini AIO Flight Controller - 35