Tar21 or XM8

I just got some ZP from the surveys, and I am planning on buying some gp and putting it towards a new AR. I have no idea which way to go. I have been using a QBZ-95 for about a year now. Love it, still my favorite gun. But I want something new. The QBZ took me about 1 week to get good with, then maybe another 2 weeks to master one shotting across maps, mostly Fortress for practice. I don't want a gun that is easy to master, because that just gets boring.

So basically, I'd like your opinions on each gun and which do you think is the better of the two.

Thanks

Comments