Nobody wants to pay big Canon money for a lens adapter when there are other options available at a fraction of the cost. But all EF / EF-S lens to EF-M adapter options are not created equally.
Meike vs Photodiox EF-M Adapter
I tested the following lenses on both adapters:
How they are similar:
Both of these adapters performed their intended function admirably. That is, autofocus, auto-exposure, and image stabilization functions (if applicable) worked just fine with EF and EF-S lenses attached. Neither came with front or back caps. Fit in the EF-M mount was nice and tight on both, with minimal lateral wiggle.
Both are similarly priced, with the Meike MK-C-AF4 being about $25-$30 and the Fotodiox Pro EF-M being about $40. Similarly priced, that is, compared to the Canon EF-M adapter that weighs in at whopping $199.
In other words: they both get the job done.
How they are different:
The Meike adapter is mostly plastic, with the exception of the front and rear mount contacts. The tripod mount itself is also plastic, although the threaded insert is brass. It’s light and compact. Comes in a plain white box with nothing else inside.
The Fotodiox adapter, on the other hand, is totally different. It’s 100% metal, with a very robust tripod mount. The finish is exceptional, and feels nearly identical to the Canon adapter. It’s heavy and a little bulky, but it has a very nice heft. The tripod mount is much larger than the MEKE and sticks out much further. The Fotodiox also comes in a nice box with some instructional material.
Which one to buy?
If your budget is really tight or maybe you are going on a long hiking excursion or perhaps international travel where every ounce/gram counts, get the Meike. It works great and is light and small.
Otherwise, spend the extra $10 and get the Fotodiox. It’s much more robust and sturdy than the Meike, and I suspect it will last longer and be able to handle repeated use/abuse far better.
Whichever one you get, I recommend also getting a spare set of EF-M front and back dust caps. Sure, these adapters are cheap, but the dust caps are really to protect your camera. The adapters will pick up dust and other small debris in your bag and that could fall into your camera when you attach it. So spend another $5 and protect your camera!