I use a 6.5" V-LCD651STX on my rig. I got it because I didn't have a good monitor to put on and it was $650 on ebay. I love it. I've never had any visibility issues with it. I haven't used the 7", but the 6.5 is a great monitor if you get is for a good price.
The only issue I've had with it is the frame lines are a pain in the ass to adjust. You have to go through several menus and the controls are pretty slow to respond. I usually just rip a piece of spike tape in half, stick it on, and call it a day.