If you can find one, the Ronix caption is a great beginner board. It is fast tracking so it can handle smaller wakes and/or larger riders. It is very stable and not squirrelly at all, but still very fun. It doesn't pearl easy and is fairly light weight, so it's easy to get up on for smaller riders.
When I was learning, I first started off on a Broadcast, then went to a LF Fish, but it wasn't until I got on the Caption that wakesurfing really clicked for me. I admit we were still very new and hadn't quite got the surf wave dialed much, but this is the board that did it for me.
It is also durable as all heck, one time some big rollers came and started pushing me too close to the transom. I put the brakes on all the way and ended up falling off the back. The board shot forward and hit the tow ring on the transom. You can barely tell it hit it.