Quarterbore's Forums - Any Opinions on DPMS vs. Armalite

I'm looking to buy my first AR style rifle (.308 Winchester/7.62 NATO) and was wondering if anybody out there has an opinion on buying DPMS over Armalite, or visa versa? I mainly want the rifle for long range shooting and am looking for accuracy as well as good tactical use. To initially save money I will probably purchase an off the shelf model, understanding that there are a lot of things that can be easily upgraded on it in the future. Any personal experience to look out for and known conveniences or inconveniences one model has over the other would be greatly appreciated.