You can find criticisms by Jason Colavito http://jcolavito.tripod.com/lostcivilizations/id14.html or Rob Havernik http://www.skepdic.com/essays/sitchin.htm if you don't like Heiser. I don't know if they're any less Christian in outlook. In Heiser's defense, he did write an open letter to Sitchen who declined a response http://www.sitchiniswrong.com/letter/letter.htm