Richdog - The number of negative posts I've seen here, compared to the hundreds of thousands of units (maybe more) that they must have sold is pretty miniscule. In general, forum posts will be negative (not just this forum), because more people come to a forum to complain or to find help than they do to say "things are great".
Also, you can pick any drive on the market, and you'll find someone somewhere who's had or is having some kind of problem with it - nothing is universally compatible and error free. If one person posts a problem in a forum, you can bet others will hit it too, so problem posts will tend to accumulate.
I don't doubt that the folks who posted problems here really have them. That said, I love my PX-708A (it's from when they first came out). When I got it, I kept my Sony DRU500A in the system too, until I was sure I was going to like the Plextor. Last month, I took out the Sony and put it in my son's system.
I post a lot in the Roxio forums, and I see a lot of posts there from people with the 708A. Some have trouble - a lot of others have none at all. Quite a few of the folks I have electronic contact with have this drive - the ones I know all like it.
Should you return it? That's up to you. Personally, based on what I've seen here and in other forums, I wouldn't return it without trying it.