We run a Brother GT-541. Couldn't be happier. The machine is reliable and fast.
I would not buy anything with epson heads. They just can't handle the viscosity of most dtg inks well. And not to mention, they are slow.
I print an average of 30-45 shirts an hour for a decent size full chest and 60-80 an hour for left chest.
In the 7 years I've owned this machine, I have not had more than 1 day of downtime with over 80,000 prints. I had to replace 1 head at $900 and the system battery $3, oh and a wiper blade $40. The maintenance isn't much at all.
The downside is it doesn't print white ink and some colors are hard to achieve.
That being said, I am looking at upgrading my printer to the Brother GT3 with 4 white heads. I will simply not have another DTG machine in here other than Brother. That machine is a tank. I am sure there are other option just as good, but the simplicity of the Brother and the reliability makes it perfect for us.