Sharp edge is shorter. Has no pinnacles. But these can be avoided on Crib Goch. Both ridges similar sharpness on the very top. I would say Crib Goch wins it for me as it's a classic way up a great mountain. Sharp edge is a back door route up a great mountain and I suspect most people go down it then back up as to put it in a route up is a bit convoluted? Imho I think they are of similar difficulty. Anoagh Eagach is a step up from both as you can't avoid the pinnacles although they are smaller. And the descent off am bodach in the east can be tricky in wet slippy conditons. The Forcan ridge in Shiel is similar to Crib Goch and an excellent route. If you want proper ridge exposure go to Skye! Great scrambling.