The Ultras have a sort of zig zag style upper and quite a plain outsole, the Quests have a fairly conventional upper and those wierd round plastic inserts in the sides of the heel. The Quests look chunkier.
Had a look at their web page and there was not a midi version of the Quest, but I could be wrong.
I have some Quests that I use for work and they have never let me down, I'm out in all weather.