I'm using this joystick on Windows 10 with the Stella emulator. I don't own the current "VCS," so I don't know how it works there. I've also only used this item in wired mode as my desktop PC doesn't have bluetooth. It showed up immediately in Windows, and using the Game Controllers item in Control Panel, I was able to test all buttons and the paddle/dial function.
In wired mode in Stella, once the emulator is properly configured to accept the right input, this controller works reasonably well. Ultimately, I think most modern users would agree that the whole design concept of this kind of controller is fundamentally flawed, so I blame the lack of precision here on that.
However, playing some of my favorite 2600 games, I can say this:
I played Pong in Video Olympics with a rotating object (the joystick here doubles as a paddle) for the first time in years. It is reasonably precise and moves quickly. However, the stick can rotate endlessly in any one direction--it doesn't stop once you've gone "to the end." The 2600 software can't handle that, so it can get confused. Still, if I were buying this just for 2600 Pong, I'd be happy.
Using it as an actual joystick is less satisfying, but it still works with some adjustments to the settings in the Stella emulator. Long story short: some games think you're using a joystick AND a rotating paddle. River Raid is nearly impossible to control until controls are custom remapped. Spider-Man is the same.
Once the proper remapping is done, then it's acceptable, but not great. It's hard to tell sometimes if you're pointing the stick "left enough" to avoid pointing down or vice-versa. I often went left when I meant to go up, for example. It's hard to reverse direction in games like River Raid and Ms. Pac-Man, and I failed several times because the stick didn't move as quickly as my mind did. However, I think the original sticks also had those kinds of problems--there's a reason we've all moved to d-pads for our controllers.
Cosmetically, this thing is a love-letter to the 2600. It has pretty lights and they illuminate when you move the stick and push the fire button. As far as this kind of design goes, it's reasonably comfortable to hold.
SUMMARY: I got all the functions I wanted to work. It's not perfect, but neither was the original 2600 controller. I'll keep this and pull it out occasionally when I'm feeling nostalgic. However, you have to be a dedicated retro gamer to buy one of these.