I've used this plan twice: once to run a sub-20 5k, and then to get my time down below 19 minutes. It's a very manageable amount of running that I was able to fit in around other commitments. The speed work is particularly helpful: I started to look forward to it after a while, and it really gave me confidence for race day. The strength exercises are also really good, and easy to follow. The second time around I ran 18:46 at Battersea Parkrun, which surpassed all my expectations! I definitely recommend giving this plan a go.