I'd look into how each rack would secure and fit with your bike(s). I can only offer my experience...
My Swagman XC2 is all metal. I've had it since 2005 /2006, and have not needed to replace any parts due to wear / failure, or do any maintenance on it. There are no plastic parts on it to break. Also, the rack is particularly easy to use. Once the metal loops are adjust to the width of the bike, all I have to do is place the bike on the rack and push the ratcheting hook down on the bike's top tube. Done. No plastic straps for the wheels or frame. For a full suspension bike like mine (pictured above), it's very simple and reliable.
But... because of the way the XC2 secures a bike (hook pushing down on the top tube), if your bike has cables or hoses running along the top tube, the hook will push them down onto the frame. Here's my hardtail bike with the cables / hoses on top:
I release all cable tension before I secure the hook, but eventually, the cables will wear through the bike's paint. I guess I could place some kind of plastic sheet under the cables (on the frame) before I secure the bike, but that would be an extra step and carrying around a sheet of plastic, which means I won't do it.
You need to get what fits your needs and your bike. Also think about how simple you want the process of loading / unloading your bike. Then pick your rack.