I haven't used white xm's.
That's a shame – getting a comparison between white and green clicky XM would be interesting as white XMs are hated, but the green ones could be usable with the reduced force. The Dell AT10* switches aren't that great either though.
I've also tried the Siig Mechanical keyboard.
Any idea what switches? They could have been SMK "Monterey" switches instead, which are nicer than current white XMs. No idea about the feel of XMs in the SIIG though.
I didn't mind the TP3 so much other than it sliding all over the desk and looking like it was stuck in the late 90's first gen iMac era where all the stuff was bubbly plastic.
Oh, so not just me, then, on both counts … see, that's where I think FILCO Zero comes in, but the 10* key variants only exist in Asia

I'm trying hard to get my hands on some blue ALPS atm at a reasonable cost, too, just to try out. Any recommendations? I think siig with blues is harder to find and pretty expensive? Anything other keyboards worth looking at?
I have an old Tulip ATK 030244, I might be the only person on the planet with one. Sits at the corner of my desk at work, connected to my PC but rarely used. Awesome sound from those blue ALPS, but it's 101-key in a non-Model M layout. From the ALPS wiki, keyboards with complicated blues:
- Some Northgate Omnikey Ultra and 101
- PC-8801mk
- Acer KB101a
- Laser
- Some Samsung/Chicony KB-5161