Which should I get?

I have the Annie-O and adore it, so my biased vote is being cast that way.

Some time ago I showed Minx's product page to my friend. Jaw-drop and all that. I saw her debating with herself whether or not to tell me to change my plans for a gift for her and then sighing sadly "but I've already got a harness".

the only difference of note is the hole size. If that makes a difference, then pick whichever you'd need. Otherwise, they're basically the same, so I'd just get the cheaper one - because then you can get another toy to go with it.