About 5 million of us manage to live up here with them, so clearly not that bad an issue.
My experience, 20 years of living in 3 different places up here, is that they can be horrid at the wrong time of year, on the wrong day, in the wrong place.
But they breed in 'waves' and it is the female who bites as she is preparing to mate. Therefore you find the first (of two or three waves) is in late May, often again in late July and occasionally again in September. If you are on day with more then 4mph of wind, they cannot fly. If you are away from water and food sources, they are unlikely to be an issue. If you are near urban areas, it is raining, it is outside the breeding season, then they are rarely an issue.
You may find you need to hide in a tent with some smidge and citronella candles, rather than sitting outside the tent. You may need to think about open campsites not woodland ones (Glencoe Campsite - shudder). You might want to time your trip well. You can buy nets an smidge.
In my 20 years of camping, canoeing, cycling, walking and more around Scotland, I can think of a few days a year where the smidge or nets come out. But for the other days in the year, not an issue.
That said, get a bad midging and it is horror. There are two types - one when you wonder if you will die, the other you hope you will die....