>>2
You can almost always find the same programs that work as U3 programs in standalone versions. For example, there is a U3 version of Firefox, but the standalone portable version works just fine. (Almost all free programs that are converted for U3 are also available this way.)
I consider U3 very annoying, because it wants to unmount the drive its own fucking way, it uses its own launcher menus, etc. It's as pointless as Iomega's old Active Disk bullshit - they are just attempts to create sub-platforms so that they can receive licensing fees from anybody who wants to sell a something with the logo on it.
If you can live without having such technology on your removable hard drives, DVD+-RWs, CD-RWs, Zip disks, floppies, etc., then you can live without having it on your USB thumbdrives.