Hitch mounted bike rack for combo of tri and kids/mountain bikes

I have an older version of this model:

http://www.thule.com/en/US/Products/BikeCarriers/Hitch/964%20Revolver.aspx

Biggest issue is that different sized bikes make it challenging to fit them all, but I've always been able to make it work with a little effort.  I usually use ties that came with it to keep the wheels from spinning and banging parts of other bikes that inevitibly are poking through spokes, etc.  But no damage to bikes has ever occurred while using it.  Seems pretty secure.

I have this one: http://www.thule.com/en/US/Products/BikeCarriers/Hitch/990XT%20Doubletrack.aspx

It is awesome. It is really easy to adjust to switch between different bikes of different shapes and sizes. And, I love that it has integrated locks so we don't have to deal with cables and such. They make one that is similar that you can get in a 4 bike model. Highly recommended.

I've heard that the Kuat Sherpa is the Creme de la Creme of this style of bike rack.  

I think I would prefer the Yakima Hold up as it clamps onto the wheel instead of the frame.  I like Yakima products because I"m familiar with them.   I"m sure the others are close in quality and cost.   I HAVE heard that the Thule version of this rack gets rusty quick... but maybe they've fixed that.