For the purposes you mention, Mud, think you could get a lot of nicer, prettier ones which are still comfortable. I've never found Clark's non-clumpy ones that suit me yet, but other people have posted some good-looking styles on here. The Merrells are also cute - my only reservation on them would be that, if walking on uneven ground a lot, I'd personally want a thicker sole.
But agree with Hellonheels and fluffles that, when sandals are needed for really serious walking/ scrabbling - up and down hills, or along cliff paths, or round ancient ruins, or whatever for hours at a time - it's probably best to go for ones which look the part and don't even pretend to be 'girly'. And which have really good support, and tough soles. Lots of people do these - including Fitflop, who have a non-glam but comfortable-looking style called Hyka.