I did a return on my stadia today and sent back everything, will report back on what exactly happens with my account, whether I get a full refund or not, etc.
To continue this, I checked my credit card today morning and got a full refund ($140 with tax) and sent my stadia back with a free shipping label from Google, so its a pretty risk free test of the product which is nice. No restocking fees or anything.
I got a key last tuesday (a day after "launch"), setup my account, tested at home with PC/xbox controller, got the box on wed, tested it at my sisters house on Wed with CCU/controller, tested at home on thursday, and decided it wasn't for me and initiated a return on thursday. Had my Pro account deactivated friday morning ("founder" status revoked, no games anymore, no Destiny F2P version exists), sent the box back friday afternoon, and had a full refund on my account friday night. Box should be arriving at Google sometime today.
So yeah, wasn't really for me, I didn't really have any issues with it but also no desire to play Destiny 2 at 1080p at random locations, don't care about Samurai Shodown, and none of Stadia games available are interesting to me (played/finished most). If they put out a sub plan or exclusive games that are interesting I may revisit. At least I have a stadia account now, although I can't really do anything with it except pay full MSRP for one of the 20 games. No f2p games at all.