Yep, no real issues with using two USB Sticks. Only difficulty I could foresee is if one of them should fail, it may be hard to determine which one has failed. This is opposed to when you use an actual drive since you can track/trace it easier based on Serial Number. Of course, I have never used USB drives myself (I all *uppity* like that... ;) ); but others may have more insight.
I totally understand about not wanting to consume SATA ports as well as costs, as long as you keep backups of your Configuration then actual re-installing and uploading a save Configuration is pretty painless.
Not that I am aware of. I am not sure why one would need to worry about encrypting the OS drives personally. As far as encryption itself (for the pools/datasets); I prefer to steer clear of that in FreeNAS as well. May want to search the forums first regarding Encryption if you are entertaining that idea.
Thanx Mirfster. My underquotes:
* I think getting to know which of the two flash drives is failing (if not both...) is just trial and error: unplug one, if the system is booting then the other one is failing.. Right?
* backups of the configuration can be made via the GUI I read. Is the configuration used on the system stored on the boot drive/disk or in the storage pool too?
* about the encryption: when the OS is handling crypto for the storage pool, it has to store crypto keys. I think one would like to store those crypto keys on safe media (like crypted flash drives). I'll read some more.