Skin So Soft is good but I got a bunch of friends to act as guinea pigs for a few anti-midge potions when we did the West Highland Way this summer. There's details of them on my website http://www.stravaiging.com/activities-scotland/wildlife/midges
By far and away the best ones (for us) were Stop Bite and Mozzy Off. In both cases the midges would land but didn't bite. At one point my arms, legs and face were a writhing black mass of midges and counting the bites at the end of the day I only had ten, mainly on my chest where they'd got trapped under my t-shirt (and where I hadn't rubbed repellent)
Cheers
Andy