Should I use AssertJ with Spock framework?

At a first glance AssertJ seems to have richer API than native Groovy collections API and that's why I wanted to use this library in my test methods. Is using AssertJ together with Spock framework considered an anti-pattern? I'm trying to leverage Groovy mechanisms as often as possible (such as any, every and similar methods on collections) but I'm not sure if it's sufficient in many cases. Does anyone have an experience in using both of these solutions together?