New Tokina lenses for EF-M

nnowak wrote:

Mirror lenses inherently suck for photography. They were bad 50 years ago and are just as bad today. New focal lengths in new mounts won't erase any of the shortcomings. It is actually embarrassing to see a company like Tokina release these things.

That's certainly the received wisdom on cats, but as ever, received wisdom mixes truths with things that aren't quite so correct.
There certainly are inherent issues with mirror lenses - doughnut bokeh, generally low contrast, slow and painful focus and so on. But it's certainly not universally true to say they're bad for photography. 
I own no fewer than 5 mirror lenses:
Centon 500mm f8 in T2 fit.

Sigma 600mm f8 in EF fit.

Vivitar Series 1 Solid Cat 600mm f8 in EF fit.
Samyang 300mm f6.3 in EF-M fit.
Tokina 400mm f8 in EF fit.
The Centon is awful. Fully deserves every word you wrote about mirror lenses. And more. It was cheap, it's a Korean made lens available under a hatful of brands, but it's very low contrast, not massively sharp, very light and pretty small for what it is. But for all the advantages of size and weight, I wouldn't recommend it to anyone.
The Vivitar - or PerkinElmer - is very different. It's incredibly short, but quite heavy, given the extra glass elements, and is actually a pretty decent performer. You want a 600mm lens for anything other than an RF camera, for which the RF f11 is a great choice, then this is going to be far better bang per buck than anything else - so long as it's not for action. Because focus is still not the easiest. But aside from that, I WOULD recommend this lens/
The Sigma is somewhere between the two. It's not brilliant, it's not terrible. Quite sharp in good light - it needs some contrast. Would I recommend it? Not especially, no, but as a cheap 600 for static work? Why  not?
The Samyang - well it's like a much smaller version of the Sigma. Performs similarly - I quite like it in full sunshine, not so much in low light. Focuses well enough with focus peaking. Would I recommend it? Yes, just about. Not a lot to carry if you need 300mm on an M camera intermittently.
The Tokina - I actually quite like this lens. It's a touch better than the Samyang/Sigma level, which means it's not bad at all. Seems to have a bit more contrast, it's really quite sharp - of course it's still not the easiest to focus, and doughnuts, but would I recommend this to someone who needs a small, cheap 400mm? Oh yes - if you're not using an R, in which case get the RF 100-400.
So on the strength of the 400mm, I very much welcome Tokina's new lenses - if they're an improvement, they'll be pretty decent. Are they universally useful? Of course not. But are they an embarrassment? Absolutely not, no, they're a welcome addition to the potential M arsenal