I guess it all depends on the purpose of the dock is for you.
For instance, I purchased two of the Apple's dock and have been very happy with it. It's very nice actually and it doesn't feel cheap (not that I would expect that from Apple anyway). It's weighted so it doesn't topple over. It's simple streamlined design.
So the purpose of this dock for me is to dock it next to my desktop. I don't forsee myself carrying this dock with me to charge my iPad. I don't see myself watching a movie using my iPad at my desktop so the portrait only position is perfect.
On the other hand, it seems like the other use for a dock is convenience of not having to hold the device while watching a movie. That would mean that you need something lightweight and small. I don't see how you need a dock for anything else other than having the iPad have someplace to rest for the night or convenience of not holding it while you're traveling somewhere.