We've been live for a couple of weeks now, still no public sign up link, just letting people in when they email to ask for an invite. We have 35 players which i'm pretty happy about!
Nobody has asked for their money back, one guy asked me to delete his account but only because he wanted to start afresh (and paid again). At least 3 people have upgraded from their sign up level after playing which is a good sign I feel, plus they sound like they are enjoying it.
I'm really glad we decided on slowly letting people in at first as there were a few bugs and inadequacies that became obvious but would have been worse with more players. One example - when developing we hardly use the in game chat and personal messages, but in real life people use it a lot more and so needed it to be better.
One of the problems with a game like this is I'm not developing and then releasing, I have a constant task of keeping an eye on a running game server and it's world. I don't mind doing it but it does draw me away from the coding.
People seem to like farming (and also looking after baby animals, a new addition) and are continuing to build out the world, I regularly log in and don't recognise where I am
Continuing to develop while people use it does however give me an invaluable insight into what they want, they'll usually say things on the global chat that help me make the game better.