Simple question just yes or no.
Looking at using this switch Eaton RF9500WS ASPIRE next to a wired GE smart switch. My question is can I stick this on the wall right next to the wired switch (which is in a single gang box)? Then use a standard double switch plate cover to make it look like all one gang box?
I’m sure I can. I just would like someone who has used this to chime in before I spend the money (50.00) and get it delivered then doesn’t quite work look like I want.
In the forums, that’s usually referred to as the Cooper RF9500. Eaton is the company, Cooper is the division, aspire is the model line.
Anyway, if you put them right next to each other the RF9500 is raised up about a third of an inch higher than the other switch. So they don’t look perfect next to each other. If your wiring has enough play you can use a lift under the other switch to raise it up and then they will lie perfectly flat. Cooper actually makes a piece to do just that assuming that the other switch is also a Cooper. I know we discussed that in the forum in the past. 
Found it:
Thank You @JDRoberts .
The switch beside it is not a Cooper it is a GE 12722. Possibly I can still use the spacer with some slight modifications to even everything out. Or put something behind the plate of the GE to shim it out. Off the top of my head is the generic spacers they make for when your drywall is not flush with your gang box.
I think I am going to give this a try until I can remodel that room and get another wire pulled in. I’m going to use this to work with another Zwave switch. Which I understand from what I’ve read is a common use.
If all else fails I’ll have it for use somewhere else later.
I’ve been doing exactly this for about a year, I think it looks totally fine.