To Upgrade or not to upgrade that is the questjion!

I have been asked by my maintenance manager, who has just gone out and bought himself a Field PG (against my best advice) if he should purchase Siemens SUS contract for step 7 rather than getting stung for upgrades when they come out. I already have the SUS contract for the 3 Field PG's in my department 1 for my desktop and 1 for my home computer. I upgrade all the time.

But I was wondering if anyone is still using step 7 version 5, or even 5.1 (latest version is 5.2) and how they manage with maintenance and upgrading of plant.

Regards

Barry Humphries