I tired the Pennzoil for about 1k, and quickly dumped it. My transmission would shift very hard and was extremely notchy with the pennzoil. I went back to the Mopar stuff and it has been fine since then. I have noticed that every 15-17K it gets a little tempermental. I think it may be time to change the fluid again.
The mopar stuff costs about $7 a quart, and you need about 4. So for about $30 bucks, it is not a huge investment for a fluid you know will work.