First of all, I have owned 11 pairs of crocs footwear:  8 Sandals and 3 shoes/mocks or loafers and for the most part, they are all pretty comfortable.
From current to oldest:  Classic Slide Sandal (this pair), Santa Cruz Loafer, Unisex Modi Sport Slide, Swiftwater Leather Moc, Band Fisherman Sandal, Baya Slide Clog, Duet Scutes Sandal (2 pairs), Yukon Slide and Yukon Slip on.

Like I said, they are all pretty comfortable with the exception that a) some are somewhat small (maybe 1/2 size).  b) Some are made of really lightweight material which won't last long such as these, (especially if you're walking on pavement).

Unfortunately my favorites are the ones that they no longer make but are heavier, sturdier and last longer:  ie:  Crocs Duet Scutes, Yukon Slide and Yukon Slip on.  On the other hand, the newer footwear are cheaper (about 1/2 the price).  So I guess in this instance, you get what you pay for.

Never the Less, as I said ... they're all pretty comfortable which is why I keep purchasing them.