To buy or not to buy...Norton 360 Premier

OK, I'm new here so please be gentle!

That decision time of the year has come round again. Should I automatically update Norton or not?

I am running Norton 360 Premier Edition on 3 PCs and use the online vault to utilise my passwords on each machine. The auto update has come through at £69.99 which as usual is far more than you can buy elsewhere. However I read that 360 is not available anymore so I assume there won't be updates if I take the auto update route OR buy a key from somewhere else.

The "new" Norton/Symantec offering can be had for £49.99 for a year (if I buy within 14 days) but without hunting around I don't know if that can be added to my 360 subscription easily or is multi device.

What's the best option? I have 30 days left on my subscription...

PS. why does the auto update ALWAYS cost so much more than you can buy it in the shops/on-line? I've been with Norton for years but don't benefit from any loyalty bonus!