I don't know a lot about Ameetec specifically, but I seem to recall that they are well thought of by most around here. Bear in mind, when asking about this or that company, you will get those that love and those that hate a particular company. Most of the time, the haters will go ahead and give you a good reason for their dislike.
Also, while AR15's all look and function similarly, all are not created equal. Some companies seem to routinely produce dog rifles, while others typically have good to excellent rifles and will work to fix the unavoidable lemon when one crops up. As far as I know, Ameetec falls into the latter category. They don't seem to be thought of as well as Bushmaster, and feelings towards DPMS vary widely. Don't know how much help there is here, but my $.02 worth. gk