david Healey , you know in your heart that Trad is best AS LONG AS YOU ARE FIT AS A FIDDLE thats the riser, it all hinges on "fit for purpose" , nobody unfit or big should entertain cleaning windows by the ladder method wfp is absolutely suited to folk with worn bodies and/or excess weight issues /vertigo and i heartily say WFP is the very best in that scenario why you are posting your question leads me to think you are wanting to stir things on the forum
All you need to know :http://www.cleanitup.co.uk/smf/index.php?topic=170006.0