@twol: Your experience is my fear. MY iPad2 worked like crap for months before I realized that there were certain router tweaks that could help. Now that it works I am hesitant to upgrade the IOS.
I should also mention that at the time I originaly discovered the problem I found out that ALL Apple devices were slow (or wouldn't connect) in my house with my Linksys router. The devices that wouldn't work right were 2 iPads, 4 iTouches, 1 iPhone. I started testing all my kids crap and realized, holy poop, it's not my iPad2 after all! It's EVERYTHING Apple makes. My "other" stuff worked fine (Blackberry, Droid, Dell laptop, Gateway laptop, Linksys USB wifi card in an old desktop).
By turning off QoS on my router, every single Apple device was suddenly fixed. My kids had never told me how slow their stuff was because they thought it was normal. OMG! Wireless DL speeds jumped from less than 1MBps to 15-20MBps! That is a drastic change. It used to take HOURS to install a new app but now it's pretty much done in seconds.