The sea wall looks lovely from a distance but is extremely bumpy with lots of short tarmac covered concrete sections at all sorts of heights.Its also commonly very windy with no shelter plus birds drop sharp shells on the road surface which can cause punctures.
I tend to avoid the coastal path for this very reason, but I did it a few weeks ago and was very pleased to discover that it has been resurfaced so it is now pretty smooth all the way. I quite enjoyed it even on 23C tyres. Hurrah!
Doesn't help much with the wind, though. I find that if you get a headwind, the coastal path and the stretch across Romney Marsh are the toughest parts of this ride - much worse than any of the hills.
There was also the "off road" section two years ago, enforced by a fairly spectacular road smash that closed the road and left me, Deniece, Tuggo and others having to carry our bikes through a field - the alternative would have been to take a detour of several miles. It would be very bad luck to get a repeat of that incident this year.
I've not done any audaxes this year yet (in fact, my membership seems to have lapsed due to a problem with the standing order not going through) but this is my local one - the start is only a few miles from home - so I may make an effort to turn out for it. Despite the over-familiarity of the roads, it's a very nice ride, not too challenging but with good varied terrain and pleasant scenery. And, as has been mentioned, excellent catering at the finish.
d.