EF-S 55-250 STM or EF-M 55-200 ??

I need a lighter more compact replacement for my EF 300 f/4 L on my M-50.
Can anyone offer an educated opinion on which of those two might be expected to be sharper? I could use the extra reach of the 250, and the extra half-stop. Price is not a consideration.
Thanks!

Looking at its results in the sample pic thread, the former looks like it could definitely work...

Since no one is answering that has the lens, I have the ef-m 18-150mm on my M5 which is super sharp. The ef-m lenses are usually made smaller and nodal points for focusing are designed for the m series canons. If you want small then I would look at the ef-m lens as I have handled a 55-200mm for a Nikon aps-c camera and it is a quite a bit longer and wider than my 18-150mm ef-m canon. I do have the adaptor that you would have to buy to use the 55-250mm by canon and it is super good. I have a ef 40mm lens on it and it is sharp but no sharper than the ef-m 18-150mm. You can google flickr and ef-m 55-200 to see some shots by that lens. Hope this helps

I have both,I would say they are both equally sharp,depends if size or price are your preference,the Efs 55-250 certainly can't be beaten on price.

I posted a couple of replies related to this over on the other thread where the same question was raised.

https://photography-on-the.net …showthread.php?​p=18867867

Thanks fellas!
I should get my refurb 55-250 tomorrow (already had the adapter and will appreciate the reach).
Quite likely I'll wind up getting the other before too long as well...