Before we begin our complain-o-thon, I would like to begin by saying the tablet will be a hampered, useless device, with no real purpose other than to make Apple lots of money. It will have a slow, outdated processor, terrible battery life, no ports what so ever, and will attract fingerprints like a mofo. It will cost 2 arms, a leg and your first born son, require a 5 year contract with Verizon at 70 bucks a month for just 3G internet access. It will not have any of the features that were rumored about. It won't be a touch screen (You have to plug in a mouse) and it won't have any memory on board. (SD card slot though... its expandable!)
...And they're going to sell a billion of them.
What complaints do you have?