I recently discovered the Onion Omega2.
Anyone used these?
Once again, yes, it may be cheaper, but with the way these are designed, by the time you outfit it the same as a Pi, you will have spent more. There is no vid port, no ethernet port, no usb port...
But you don't need everything on the Pi, for now.
If you later decide to repurpose the Omega, you will be spending more, IF parts are to be found. What if the 3 is out by then and not interchangeable?
Here is another thing you may want to consider, you can connect a mouse, keyboard and monitor right to a pi and troubleshoot. Arduino, you make a change, compile code, upload, then cross your fingers that you fixed it. No? Make a change, recompile code and try again.
I've used Arduino on 3d printers then switched to Smoothie and Raspberry Pi, Smoothie uses a single, plain text config file, Pi you can diagnose it directly, you might not think it's a big deal, but I tell you what, it is a world of difference. I really, really hate trying to troubleshoot Arduino. You can spend as much time trying to get the firmware to flash as you spend diagnosing it, Smoothie and pi you pull the card and edit a file and or connect direct. The same goes for connections, their claim to fame is being cheap, problem is, it's not hard to see why it's cheap, they stripped it of everything. I'd much rather spend a little more and just get a Pi, rather than trying to solder a usb connection, HDMI port or ethernet port to that thing. It's just not worth the hassle
I know quite a few people with Arduinos, LOTS of them, and most get used once then shoved in a box. It's a single use controller. This will be the same because once you solder some connections you sure aren't going to want to deal with it again.
Also, $60 for a Pi?
I know you pay more in Australia, but they retail for $35 here and you can sometimes find the Zero for $5, which has usb and hdmi built in.