My partner has exactly these, after much dithering (and I mean for months if not years) he went for these, already had these sunglasses and paid about fifty quid in total for the insert+lenses and says they're brill, he likes that it will really easy to just get the insert updated if his prescription changes.
At Brighton Half yesterday I did exactly what Catalin describes and I came in at 2:00:08 - but as my previous pb was 2:09 and I was hoping to get somewhere near 2:05 I'm actually really chuffed to get within 8 secs of sub 2! For me it was having the confidence to keep up a faster pace than I'd planned because it felt comfortable on the day and just gritting my teeth and hanging on for the last 3 miles! Good luck!
I like my Aldi buffs even more for running especially as they're about ??3 each . Stock up next time they're on sale. Otherwise +1 for Vaseline - thin layer all over your face - acts as a barrier against the cold and wind