Backup is probably the biggest probel the iPad has. Visit the Apple support forums and you'll find a ton of posts about the problem.

I used to have multi-hour backups. Then I noticed that I was using my iPod touch cable. I switched to the iPad cable (the connector is twice as big) and the problem went away.

You can also click the small X in the progress window during the backup phase of the synch and it will stop the backup and let you get on with the process. Just make sure you have everything you want off of the iPad before you do the upgrade.

Mine took 24 hours to update. It looked like it was hung but I let it go. Just let it run and you will be fine.

I am still on the 3.2.1 Ver and plan to stay with this for now, works fine and no real improvements needed to meet my needs.

Folders in 4.2.1 are nice, multitasking (sort of) is nice, too.
But I still may go back to 3.2.
I didn't really miss a lot with 3.2, airprint doesn't work properly because I don't have a hp printer and won't by one just because of apple playing marketing for hp. Well, airprint was the main reason to upgrade and it worked with all the betas on my printer, and now I cannot get it to work.
But I miss my hardware screen-lock.

i have no issues what so ever with 421.
back ups are fast
wifi is great...
operates very snappy.

Back ups are faster with is 4.2., with the previous 3.2.2, it took longer

I too am a little worried about updating - I want the new features, most of them, but my past experience with updating my iPod OS have not been good, requiring me having to go to the Apple Store, not that I minded that :-), to get the PROs to fix it - and its happened twice! My conclusion was that my iPod was trying to do three or four things at once and that caused the problem; 1) since I use a Windows PC, I plug in the iPod and the first thing it does is load the device, 2) iTunes says, "Oh, one of my devices just hooked up, I should open, 3) iTunes starts looking for updates, and 4) once found, wants to begin installing the update.

Next time, I think I'll let it finish one thing at a time. But, once I get over this fear, I'm ready.

For a company that prides itself on making things "just work", they sure have tied their products to a giant pile of dog @&#@ called iTunes. Seriously, there is no reason it should take 4 hours to backup an iPad that is half full with media, especially when you arent even backing up the 4 gb of music of the 8gb of data that is on it. iTunes is horrible, and it really taints every iOS device. How can these devices be "magical" when you HAVE to use this horrible iTunes for it to function? They can't.

My gosh. Am I happy to only have some books, mags and games on my iPad.
It takes about 30secs to back up and my memory on the iPad is more or less an empty slate.
I couldn't stand the idea of yet another media database on my PC which adds to the data duplicates I already have.
Music is on my mp3 player, pictures are done exclusively in an adequate program and the movies I watch (if I do so) play in cinemas or on TV. So I told iTunes to only take care of the apps.
As for the books and mags, I use goodreader mostly. It doesn't need yet another database and a watchdog for folders hogging down my PC.

Is it true that iTunes functions much smoother on OSX when compared to Windows?