Hey @janvda! That’s indeed a good question and something we think quite a bit about.
The large majority of the devices on balenaCloud are Raspberry Pis, followed by (far behind) Intel NUCs (or devices using the NUC image, such as Intel Compute Sticks), the BeagleBone family, and Jetson TX2s. We are also start to see the BalenaFin boards show up in our stats, which is quite cool for an unreleased device. The other device types are pretty much in the long tail.
As for what hardware to use for your project, it depends on your requirements really (I guess there has to be more than just “power” to consider), if you have some thoughts on what lines you are drawing (in terms of architecture / power / other properties like peripherals), we - or others on the forums! - can recommend stuff more! So is there anything you’d like to expand on that?
In general, there are smaller x86 boards (the UP Board) that can be quite powerful and similar form factor, or other ARM boards that pack more punch (but have smaller communities for information, as of now, which doesn’t reflect on their qualities just their age), or e.g. the Jetson family if you would need GPU compute uses, for example. It’s not really a linear line of power, but it’s a whole multidimensional arrangement. I think many of these will be a lot more popular in the future (in absolute terms, as in relative terms Raspberry Pi has quite a bit of a lead…