50 minute periods - elite tech or naff?

For context I go to a grammar school that is on the most part very traditional and fairly strict - for example our sixth form can't leave during the day, no free periods etc (oops sorry back to GCSE) but one thing I do love is put 6x50 minute period day. Compared to the neighbouring schools who do 5x60 min and 4x70 min the people I speak to are surprised by how short they are - but I really think this is the best policy I've ever seen from my school. The idea behind it is similar to that of revision where you keep moving and varied to stop getting distracted, but long enough so that you actually get enough work done. The 6 periods typically gives me a good variety in the day so on average you'll have at least a couple of good lessons every day. I want to finish with a question and just ask everyone what they think of their period lengths and if anyone else also has <60 minute periods and what you think of them.