The SXmini's build quality is very good. The board is actually secured with screws, and is very neatly done. The build quality rivals many of the high-end mods I've owned over the years. Quite impressive for a production device. Here is a pic of the S Class internals posted by another member in the SXmini thread:
I had a Hana V4d recently, and it worked for a few days before the display scrambled on me. I did get a feel for how the temp-protection worked, and must say that I prefer the vape experience from the SXmini M Class. The Power modes allow me to "tailor" the vape to my liking, picking up different flavor notes that I haven't noticed before.
I am currently running an Ni200 coil head@ 25.0J / 425F in the SMOK Gimlet. The head is speced for 0.20 ohms, and is reading 0.22 on the M Class. Setup was a breeze, and performance has remained consistent. I am getting a nice, full, thick vape.. Very enjoyable.

Like the S Class, I appreciate the accurate 3 decimal place readings for the resistance, and real-time battery voltage (when in power / wattage mode).. The device also displays an accurate depiction of battery sag under load.. Just an overall wealth of accurate information at a glance.
The SXmini S Class has been practically glued to my hand since last November.. The M Class has now followed suit...
