I also finished soldering my switches tonight. Had only 1 switch that just didn't work, but it wasn't the activation above bump issue or the chattering issue that folks have been talking about. It just didn't register anything at all.
No special care taken on the soldering, mostly out of inexperience - I learned to solder literally this morning so I don't think it was probably especially well done. I also had to desolder about 6 switches because of my messups, and none of those switches ended up having issues either. I used a Weller WTS100 at max heat. Probably just got lucky with an especially problem-free batch!
This is very interesting, that makes the melting theory a little bit weaker.
My first impressions on the 67g tactile switches is generally very positive. I didn't like their feel with SA caps, but swapping over to a GMK set made the clickiness come alive. Very nice bounce to the keys - feels really crisp and enjoyable to type on. Like em even more than the ergo-clears on my GON, and that's saying something.
Could this may be related with the weight of the caps?
Re: the heat thing: sounds right. I mean, I don't know if my iron was that hot, even at max heat - it's one of the lower-end Weller and the less-than-max settings were barely melting the solder (standard 60/40 rosin). I dunno, maybe the solder job is better than I think, but I doubt it. It does seem weird to me that something like heat transfer / melting point of the switch case bottom would be inconsistent set-to-set - since it's a property of the material seems like that wouldn't change much. But I'm far from an expert on the materials side of things.
Re: the feel of SA: I think it's partly the key weight and partly the fact that these seem to have just a bit more side-to-side travel than standard Cherry MX. I haven't had Gateron before so not sure how they compare. But I felt like keys were traveling in not-purely-up-and-down directions a bit more often than I'm used to, and that's a lot more noticeable / unpleasant with the taller SA keys.
I will say that after slightly more extended use tonight, I'm really starting to love the clear housing, especially w/ having these on a WKL board with RGB bottom LEDs. It's a nice subtle glow around the key bottoms that almost completely eliminates the urge for in-switch LEDs for me, at least in this build. I do hope we eventually see some custom PCBs allowing for in-switch RGB to take advantage of that neat future-proofing of the Zealios.