I'm getting a lot of iOS 4.2 related questions in at the moment so I've decided to compile a quick listing of initial thoughts based on my limited exposure to this new release.
- Install went without a hitch on all iPhones and iPads here. No problems to report.
- All apps I've tested seem happy with the new update (I have currently have 70 apps installed on the iPad and 115 in the iPhone).
- Both iPhone and iPad seem faster and snappier. Not sure if this is because it's a clean install or the new OS - time will tell.
- Backing up the iPad feels faster than before. Not a lot faster but certainly a little faster. Again, this may change over time as the install gets used. For now, I'm happy.
- Finally folders on the iPad. Will take time to properly organize things later, then it'll take time for me to remember where everything is, but eventually it will be a time saver.
- Jailbreak ... the advice is to forget about it for now until updated tools are released.
Verdict ... go for it (unless you have/want to jailbreak, in which case, leave it a while).