Have it myself - it's good enough. No issues in city, but your signal will go in and out if you take any car trips. Best to download maps of wherever you're going beforehand.

I'm not entirely sure, but I think I read it has something to do with prioritization. It uses t-mobile towers, but when they're sparse the t-mobile customers get priority to the towers.

Feel free to send a message to me for a referral code, I believe if you sign up with one we both get a free month.