In reply to Mike Stephens:
The shelterstone jacket is essentially the old fitzroy jacket. Both the Fitzroy jacket and the Shelterstone jacket are water resistant but are not waterproof, however the gore-tex infinium outer of the new Fizroy will give more weather resistance.
The new Fitzroy also uses a warmer insulation whilst the Shelterstone uses polarloft.
If you enjoyed using the old Fizroy and are on a budget the Shelterstone will be great. If you want more performance and have the budget the new Fizroy is the way to go !