I'm running GW7.0.3HP2 on NW65SP7.
I have 50 users, 1 Domain, 1 MTA, 3 POs, GWIA, WebAccess (all running on NW like a charm with very happy users.)
I have also BES 4.1.4 for the BlackBerries.

My plan is to upgrade to GW8 HP1 on NW65SP8.

1- Is there any stability issues for one or more of the products/agents?
2- Any issues with BES + GW 8 with more than one PO? At RIM website they say they support GW 7 or later.
3- Should I wait for SP1?
4- Should I migrate from NW to Windows or Linux? My intention is to keep on NW until I need a hardware upgrade.
5- It looks that the upgrade path, time, and difficulty is similar to upgrading from 7.0.2 to 7.0.3 or 7.0.3 HP2, is this right?
6- I use BackupExec 9.1, any issues with the new GWTSA?
7- In case things turn ugly, is it easy to roll back to GW 7? What is the procedure?
8- Any other considerations?

Sorry for the question bombardment, and thank you in advance,