Have done some fairly exhaustive testing with both Google Home and Alexa, but not long term obviously. In the end, I've concluded that while this is a very viable, low cost solution for non-critical applications, it is not without its issues. With Alexa it's a non-starter unfortunately, but reliable (with one exception) on Google Home. YMMV.
Cost for me actually turned out to be very low. I was in Lowes and they had both the toggle type and paddle type kits on clearance for just under $15 CAD each, so I picked up two of them.
Here's the back of the two types. There's a difference on the back, but on the inside they're almost identical. The paddle type is slightly slower because of the longer travel distance of the linear gear required.
Removal is simple. Four screws and the front cover/button pops off. One of the screws is concealed under the anti-slip pads. Once all the screws are loosened, I just remove one of them completely and push a small screw driver in the hole. The front pops right off.
Here's the inside of the paddle type, One of the limit switches is hidden beneath the circuit board. They are just press-fit into the plastic and pry up easily. There are also two Neodymium magnets inside so if you want to combine this board with the latching relay build posted above, you’re set in that regard.
The limit switches provide nice contacts for low voltage circuits. You need to test to see which wire is the actual common on each limit switch. In a circuit where you were actually going to use both the NO and NC terminals of the switch, you would always make sure the ground wire was soldered to the Common terminal. However, the assemblers in the factory would have been instructed to take any of those two wires and solder them to either the NO or Common terminals. Which one wouldn't matter for this application, as long as it wasn't the NC terminal. For our application, it does matter. So if I'm using both switches to close a contact, I would move the ground wire of the limit switch on the right of this Switchmate so it is on the actual common terminal. That will prevent the circuit I'm closing from receiving any voltage (a true dry contact).
Soldering of our wires for closing (or opening) the contact will be to the top and bottom terminals of the switch (sharing the top terminal with the ground wire from the Switchmate.
Performance
I tested the distance from the bridge (Outlet) to a Switchmate switch and had no problem 40 feet away, semi-clear line of site (some obstructions from the building, window, and brick). At 40 feet non-line of sight, it didn't work, but from 30 feet away, it worked even when the Switchmate switch was behind double-brick.
Integration
This part is a bit disappointing with Alexa. As long as you are using the Outlet for bridging the BLE connection to WiFi, the Alexa option will appear in the app. Connection is all done by code. No Switchmate cloud account required, which is a refreshing change from the norm. The connection to Alexa works, and the devices show up as an outlet and a switch, but the results are disappointing when you try to connect them to HE in an Alexa routine. The device turns ON, but the status turns OFF for a second, then back on. This is enough to really mess things up. The device state also seems to bounce on Alexa. I had a frequent problem, where even if I made two separate momentary Virtual Motion Sensors as Switch (one for ON and one for OFF), I still would get the device bouncing states. Turn it on and it would go ON, but then the device would turn off by itself roughly 30 seconds later. Same would happen with ON. Eventually, if I issued too many of one ON or OFF command, the device would get out of sync.
On Google Home, this did not happen, except for OFF. The issue was solved by turning the device off, then roughly 30 seconds later, send the command for OFF again. After the second time sending the OFF command, it didn't turn back on again. This only happened with Google Home in the OFF direction. Control of the switch from HE via Google Home was done with Google Assistant Relay.
Warning: Do not have the Alexa skill enabled at the same time as the Google Home integration, or you will get the unstable fluctuation between ON and OFF.
Conclusion:
Perfect solution? Absolutely not. There's no state feedback, but you could add one by wiring the read switch of a contact sensor to one of the NC and Common terminals of one of the limit switches, but that makes the whole thing more expensive unless you got some contact sensors for dirt cheap or free.
Another issue is that occasional bounce, where you've had Google Assistant Relay turn the device off, and around 30 seconds later, it suddenly turns itself back on. Easily solved I found by just issuing a second OFF command which could easily be built into a rule. Still, this should only be used for applications where that would not cause an issue, or that absolute state need not always be correct, lest a major problem would result when no external sensor was used to relay the current state back to HE.
Other than that, I'm actually pretty surprised at how versatile these are, and I already have some ideas of places I can use them where if the device state got out of sync, it wouldn't be the end of the world for me. The price was definitely right and the effort very minimal.
