If you spend some time in Edinburgh, this is a must do break from the city. From the outskirts of Edinburgh, this won't take you too long. It is rather steep, so while people in good shape reach the top in 15-20 minutes, others will prefer a slower pace. There are several paths to the top. All got some steep sections, but this is a walk for mostly everyone. On to the top you will have to walk sections with rugged stones that will be slippery in wet weather. Just beware, and good shoes is a plus.
It is unquestionably worth the effort. You are treated with great views of Edinburgh and surrounding area. Highly recommended!