The problem for me with this subject is to buy the best, easiest and cheapest method to stay dry. As I've experienced rain over the past 10 years or so, it can range from heavy downpours to fine drizzle, long or short in duration and is often intermittent, with or without different types of wind. My experience is that rain periods, light, heavy, with wind or not, tend to be far less in duration than dry periods.
I use one of two options, the first is to wear my b*m length, single skin full-zip jacket, (a Marmot Precip, about £60 brand new I think?) a rain skirt, and my gaiters and the second option is to use my long length, single skin full-zip coat, (made by Champion, £15) and gaiters. The gaiters are essential wear in both instances. The long coat works best on undulating landscapes, the short jacket and rain skirt tends to work better in the mountains. The difference tends to be about stride length, on undulating hikes, my stride length is more or less the same, in mountains getting across rocky landscapes often involves longer strides when clambering over rocks and other obstacles.
With both jackets, I don't really worry about being hot, when there's a lull in the weather I just unzip the jacket or coat and let the circulating air cool and dry me off. Obviously given an ideal, I don't want to get hot in the first place, but in my experience, a waterproof and cool jacket does not really exist, no matter what the adverts say!