Here's a review of my IBM Model M 122, part number 1390888.
It was made on 10th March 1987 by IBM UK in Greenock, Scotland.
It's your usual Model M; it has membrane buckling springs, two-part dye-sublimated PBT keycaps, etc. As far as I'm aware, it was supposed to be used with the IBM 3270 terminal.
Buckling springs
You may have noticed I said membrane buckling springs. Yes, you read correctly. This is, in fact, a membrane keyboard.
When you press a key, a spring buckles. When the spring buckles, it pushes a little hammer onto contacts on a plastic membrane assembly, which completes a circuit, actuating the key.
Before I say anything about key feel, let me make it clear that key feel is a matter of personal taste. A switch I like could be a switch you dislike and vice versa.
This keyboard is like nothing else I've typed on.
The tactility is sharp and crisp. There's not loads of tactility, but since it's quite sharp, you can really feel it.
When you push the spring, the spring pushes your finger back. It feels like you're typing with the keyboard, not on it.
I can't detect any scratchiness, it's just nice and smooth.
This thing is ridiculously loud. Every keystroke creates a distinctive high-pitched ping, which I love.
Even with my headphones on, it's really loud. It makes my previous keyboard (Dell AT102 w/ SKCM Black) sound silent in comparison.
If you don't like loud or pingy, avoid buckling springs.
This keyboard doesn't have n-key rollover. Might be a dealbreaker for some, but it hasn't been a problem for me.
Model Ms have 2 key rollover, however this M122 usually allows me to press up to 4 keys at a time.
(this is the seller's photo, I've taken only one good photo of this keyboard and I've already used it)
The build quality
The build quality is excellent.
There's very little case flex when twisted. If I put pressure on the case, it creaks a bit. During normal use, there's no creaking.
Model Ms usually have PVC cases, but for some reason, my keyboard's case is made of ABS. I've been told the Greenock factory would occasionally make cases out of ABS.
The keycaps are very nice, they're two-part dye-sublimated PBT.
They feel great, the legends are sharp as a whistle and the two-part design makes swapping the caps extremely easy.
Of course, with this keyboard being nearly 34 years old, a lot of the keycaps' texture has worn off — particularly on the numpad, enter and Daten Freigabe keys.
The stabilisers are great. In the 2 weeks I've been using this keyboard, I haven't noticed any wobbling or rattling.
If I try to move them, the spacebar rattles a bit but the backspace and right shift stay put.
On the inside, it's got a thick steel backplate with a rainbow-ish effect, which looks great.
It's got the usual plastic rivets, which is the main weak point of this keyboard. My board could do with a bolt mod, which I'll be doing soon.
It has a thick, grey coiled cable with a 240 degree 5-pin DIN connector on the end.
(again, the seller's photo)
Final thoughts
If you want a well-built keyboard with a crisp, tactile key feel then look no further.
Just try not to overpay for one of these. It's good, but not worth what some people ask for these on eBay. Especially when you have to convert it and you risk needing to do a bolt mod.
I'm talking about Model Ms in general here - not just the 122.
I paid £100 for this keyboard (that's $138.18). I'm happy with that and I feel like it was worth the money. But I don't think it's worth what a lot of eBay sellers ask for these.
If you can't find one at a reasonable price, just keep looking. You'll find one eventually.
There are a few little things that I'm not a fan of. They're not dealbreakers, but I feel like I should mention them anyway.
First thing is the tilde key and left function keys don't work with a Soarer's converter unless you map them. It's possible to map them, just works a bit differently than mapping other keys since they don't seem to send scan codes.
Second thing is that this doesn't have a print screen key. Again, it's a converter thing. Just have to map it, which I haven't got around to.
Third thing is how expensive these are. It was worth what I paid but damn that was a lot of money
TL;DR - built like a tank, switches feel great, worth every penny.