Apex Mega - right arm about where a watch would sit.
3 days post install and it reads pretty well (phone + medium/heavy case + MFGC repeater).
Phone
The location works for what I’ll be using it for. Phone reads are a bit more awkward than I had envisioned, but that is due to the placement of the NFC antenna on the Galaxy S23. It is low, about a third of the way from the bottom which is exactly where my hands are when holding the phone.
I hold my phone in my left hand and operate it with my right. To get consistent reads I have to either let the phone slide down so I’m gripping it underneath at the top, get the read, then push it back up so I’m holding the bottom and resume typing/tapping, etc. Or I can awkwardly grab it by the very bottom edges, kind of roll the chip across the back and get good but slightly less consistent reads, then move my hand back up to a normal grip.
If the app I’m using doesn’t close the “read” operation with an inadvertent touch, then I can grip the phone on its left side by the edge. That feels a lot quicker and smoother, but has about a 50/50 chance of accidentally tapping the left edge of the screen.
Desktop
Works great for uses where you are prompted to present the chip to the reader, then the app does its thing.
But for apps that expect a smart card to already be present on the reader when the action is initiated, its kind of a PITA. For example, when unlocking a KeePassXC database, you can’t preselct the “password + yubikey” option like you do on Android. Instead, you have to have the card present on the reader, then click the refresh button to show it as an option, then click unlock.
With the chip on my dominate, mouse-using hand that is kind of impossible. Thankfully the app allows tab selection and space to press the refresh button. So the flow is type in password, hit tab to focus the refresh button, place mouse-using hand on the reader, press space with left hand to click the button, yubikey applet is found and selected automatically, then use same left hand to hit enter, opening the vault.