I'm not sure a switch tester is that great to estimate the noise a full keyboard will make, but that's better than nothing...
I'm more and more thinking I'll use ALPS to build my (slightly modified) Ergodox.
It's not easy, though... Not pin compatible, far less options for PBT keycaps, and I think they all require a plate :/
I haven't dabbled in making my own keyboard yet (although will probably do an ergodox build as well whenever i can afford it).
Yea it's a bit shame about keycaps... I've actually kinda considered looking into mass manufacture alps keycaps but honestly don't know where to start and have no experience creating a business... Also it sounds super hard. But the though has crossed my mind!
You can get adapters though. They're not cheap, but someone from ehm... Geekhack? made a 3D Printer model you can order:
https://www.shapeways.com/product/9J3P8UFW7/alps-to-mx-120-stems?optionId=56261645
I have a box of tai hao miamis that are just waiting to be added on my modded matias full size board (paracord in the same colours as the miami set, Matte white spray painted terribly, gonna redo it whenever). But i can't really justify the adapter cost.. So, i've yet to try it out.
The forum thread where the guy posted it says that they work fine with matias switches, but ymmv. Better to get in contact with the guy directly if there's any doubts.
Also kind of want the tai hao paradise set (baby miami and unicorn tears) that's up on massdrop atm. Gotta get the adapters first.
The closest i've come to having the same feel as matias switches is mx clears, but ugh... Cherrys feel so cheap and hollow and plasticky and meh. The blues are also kind of okay but one might as well just pierce your ears with an ice pick because you'll go insane by the sound.
I swear, my former roommate hade blues and that shit traveled through two doors, a hallway and a pair of sennheiser hd25-ii. You know, the DJ standard for using in clubs because of their ability to block out noise.
This was 4-5 years ago and just thinking about it makes me mad.
Fake Edit:
He was also a programmer who worked almost every day after he got home from his workplace.