Hi, I love merrel, too. Also Keen makes some VERY comfy sandals and shoes. Clarks and Born have kept me comfy at WDW, too.
I always worry about my footwear. If my feet hurt my whole body aches.
I really have found that the more pricey shoes are definitely more supportive and work better for me. It is worth the investment. I used to be sooooo achy after a long day and now that I wear good quality shoes - also I buy 1/2 to 1 size larger than I used to - I am so much better off!!
Good Luck!!