I have had a Tempest since June and would highly recommend it. Plus points over the Pickenflick:
Thru axles front and rear on the tempest which are much better than qr when using disk brakes
Greater clearance on the gravel fork specced on the tempest over the cyclo cross fork on the Pickenflick
I have run 700c wheels with 40 c tyres for road riding including a few club runs and although heavier than my carbon bike it very comfortable over long distances.
Also did the Yorkshire True Grit with 650b wheels and 49c gravelkings and it was perfect, flew past people with skinnier tyres with little risk of pinch flats. I have also run it on the road with WTB horizon 47c tyres and it is just as fast as 700c on the rough roads round Harrogate.
email me if you want some photos of the bike
richwak@yahoo.co.uk