I hadn't been expecting much from my (tr)uSDX and was skeptical as to whether or not QSO's could be made that were not pre-arranged.
After 3 POTA activations with the tiny rig, it's clear to me that QSO's are quite easily made on either of the two modes I used.
The popping sound while sending CW is annoying, but not overly so. It is evident whether using headphones or the built-in speaker. For a long CW ragchew, it would - for me - be a showstopper...but for a POTA activation, it's not so bad. I even got used to it after a few exchanges.
I was pleasantly surprised at the reports of the rig's audio. For a tiny embedded mic, I think the reports are better than I'd hoped. I had been considering an external mic, like the kit offered by the QRP Guys but I think I'll just leave the rig as is - I'm really not a phone op anyway.
It'll be fun to watch this rig develop over the coming months. DL2MAN has plans to add more bands to the rig's capabilities. Right now it covers 20, 30, 40, 60 and 80 meters. 10-17m coverage is, I believe, in the works.