Interesting.... any caveats? It's a major investment for me, and would be my daily driver (instead of external monitors, which I find too large when flanking MBP screen. Any feedback (positive or negative) would be much appreciated!!
Sorry for not replying earlier, been quite busy.
I made some tests with my M1 Mac mini
- Main monitor: 4k display (via HDMI)
- Virtual monitors (all connected wirelessly, but of course Luna requires a USB C dongle on the Mac, which will prevent the connection of a USB C monitor on M1):
Sidecar ,
Duet pro,
Luna display, all used at the same time on 3 iPad pros, 2 connected to the Magic keyboard and one to the logitech combo touch (using the smart connector)
Here are my results:
1. Touch support
Only Sidecar does not support touch, but you can scroll with 2 fingers and pinch to zoom.
MacOS does not support multitouch so for instance you can scroll with 2 fingers but not with one like on a tablet.
So I also tried Windows via Parallels: Luna does support multitouch, but not Duet (and of course Sidecar is even more limited)
2. Pencil support
All 3 support the pencil well and they all have similar latency, it feels the best with Duet but simply because they use software to trick you into believing it's better (they "fill the gap"), but still it's a slight bonus.
3. iPad trackpad support
Sidecar does not support it. Duet and Luna fully do, but in Luna it's too fast on MacOS, not great, but it works well in Windows. Duet works great with both MacOS and Windows.
Please not that trackpad can only be used in the iPad screen, not on the physical monitor or on a different iPad (so you need a mouse or trackpad connected to the Mac to move between displays)
4. Keyboard support
They all support the iPad keyboard but Duet does not work with some specific non-English characters. Keyboard input works in every screen from any device.
5. Framerate
Seems good, probably 60FPS in every display.
6. Connection speed
Sidecar is the fastest to connect to the iPad, the other 2 are slower, but this could be annoying only if you connect and disconnect the iPad many times during the day
Important, you can easily minimize sidecar if you want to use iPadOS, if you do it with Duet, it will not disconnect but take like 10-20 seconds to readjust the resolution (very annoying), with Luna it will work fine for a few seconds then it disconnects and you have to reconnect again.
7. Sound
None support sound
8. Price
Sidecar is free. Only works with MacOS
Luna costs $140 for the Dongle. Works with both Macs and Windows PCs.
Duet: the wired app is $15-20 I think. Duet air (wireless, no pencil support) is $2/month, duet pro (pencil support) is $4/month. Annual prices are $25 for duet air and $35 for pro.
Duet works with Windows and Android (but Mac to Android is extremely laggy, while Windows to Android is good) including Desktop to Desktop, but the desktop to desktop latency is not great, so it's only good for static content.
Conclusion
No solution is perfect, the most limited is sidecar, but it's also free. But the others allow to use up to 3 iPads at the same time and have touch/trackpad support (each solution support 1 iPad, but they can all work in parallel). Choosing between Luna and Duet depends on your use case. If you don't need the pencil and are fine with wired, Duet is much cheaper. If you use Parallels often Luna wins. If you want to use a physical USB C monitor with a M1 (non pro) device, only duet is an option.