A nice and pleseant run, as others have said there are issues with the level of competence of other road users in parts. If, when doing this run, you head east of the A602 (East of Stevenage) there are some amazing roads around little towns and villages such as Walkern and the like.
A good road to sharpen your skills. A mixture of fast corners with the occasional tighter corner it can be quite busy at times, best to go during the week. IMO the best section is between Codicote to Langley.
A great run, a fair bit of traffic during the week, not so bad on the weekend. Take extra care near Codicote and the two garden centres, these seem to attract an large volume of blind elderly drivers.
Watch out for suicidal Deer and phesants, there are a lot about particularly past Knebworth house. Occasional Police presence on the approach to Hitchin in 30 limit near A602 roundabout and sometimes lurking in the bus shelter on the right as you come into Codicote from Hitchin.
some good twisty fast bends, best time is during the week when no sunday drivers are out