I think Ehrman and Aslan are both interesting writers and pretty honest in what they present (unlike some religiously oriented types we have all read that will say anything to support their (current) teaching or belief.
They have different perspectives. Erhman is more theological, Aslan is more oriented to the historic. They both wander into the realm of the other pretty comfortably, but they are essentially focused on different things. I think that they both have good information to offer. Both are easy reads in some cases. Ehrman has some more scholarly works out, I think and Aslan might fairly be construed as more of a writer for the common man. I like them both a lot. Both are in my library.