I understand both sides of the argument, as you can pick up a used A2 for around $50-60 shipped if you're patient, as opposed to $90. BUT, I picked up an A20 that was apparently working great, but when I powered it off over night, it had the audio issue. The seller was great and stepped up, but still, you get a player and save $30, but it's completely as-is. Nothing like putting in a dvd for your son, expecting to get a few minutes to make breakfast, and find the player isn't working.
On the other hand, these are new units from Toshiba, and I'd have to assume you'd get a full one year warranty on these. Sure, you could have a problem on day 366, but at least you have the opportunity to put it through many discs before that time is up.
A gambler can get a better deal, but sometimes it's worth the few extra bucks for a new unit that you can have a bit more faith in. Glad I thought about this from that response above, because I thought it was quite high, but it gives an interesting alternative.