As I posted in another thread...
A few key things to do for a successful jailbreak on both iPad and iPhone 4s
1. Make sure you are on latest iTunes
2. Backup your device. Make sure your backup is not password protected
3. Settings / general / reset and erase all settings and content
4. Once device has rebooted, setup as new device then once on springboard turn off wifi
5. Run jailbreak tool. Should be very quick as the device is stock.
6. Once finished turn on wifi and click the greenpois0n app
7. If fails do the VPN trick, Device will reboot, then run cydia.
8. Restore from backup.
The reason people are experiencing long or failed jailbreaks is due to having content already on he device. For the first time this tool is using a multitude of new methods including using a backup during the JB. If you are having troubles just restore to new device and start again from fresh.
I've done two iPads today on 2 diff laptops and they were both very smooth. BTW I used windows absinthe tool. Also remember if you are on Windows 7 run as administrator and also try running in XP mode if the program is cashing.
Happy jail breaking