Well, it seems like the main differences between the two are the materials and the weights. They're both made of awesome materials that are super easy to clean/sanitize, though obviously as a cyberskin, Outlaw is going to feel more real and have a lot more give to it.
Outlaw seems like a better choice if you want something that's less likely to cause bruising if you or your girlfriend are thrusting it and get a little rough. It has the same girth for the entire length though, so there's no option to switch ends if you start getting uncomfortable but still want penetration, while the Eleven does provide you with that choice.
I'd say if you want realistic and large, try Outlaw.
If an unyielding, weighty toy capable of temperature play is more your thing, I'd go for the Eleven. Just be very, very careful with it.