In reply to iamaclimber:
I have two of this years Aldi cycling shells the normal £18 and the pro version (£30) , i always wear a baselayer either lambswool or merino the normal model is thicker more windproof showerproof and less breathable. Initially it is very warm but if the air temp warms, or if i am really going for it ( I ride sportives) afters 2hr + my base layer gets saturated and i will actually start to feel colder , with the pro model you start off colder as it is thinner but will stay comfortable as you warm up and it breaths more therefore you stay drier. The pockets in the cheap one are really good though, they are larger, deeper and easy to get into while your cycling even with thick gloves. You can carry loads of food or spares or whatever.