In reply to Richard Gilbert: I'd say that they are pretty similar. Pertex Endurance in the shop seemed very similar to the drilite loft stuff which on the shoulders and arms of the fitzroy. Problem with the fitzroy is that it uses a different, less water resistant fabric on the main body.
I'd say the fitzroy is generally nicer. Better hood, and tricot? lined pockets. I have the generator jacket already, but wanted something with a hood hence looking for something else. I've had no other complaints.
All these jackets seem to be very similar. :-/