Kinda late to the topic here, but there is one issue I've had with mine. The image has a strange bow in the center, top to bottom. 'Bow' affects the image horizontally. This is vertical, so there's no adjustment parametre for it. I haven't been able to get it to anyone in-person, but those I've explained the issue to, including the regional vendor for Billabs, have said they think it's a tube defect. (Otherwise, the unit works well...but it would be nice for the image to be 'straight'.)
Unfortunately, Billabs is basically a distributor, and it's been hard to co-ordinate with them. Then I have to travel 120 miles to the regional vendor for replacement. About two months ago, I told Billabs I was going to be up there for something else (this is three weeks advance notice) and that it'd be convenient if I could make the switch then. They blew me off.