Ah, hell. I want in on this.
I'm certainly not enough of a machinist or gunsmith or engineer to offer a qualified opinion as to which is better.
But as usual, I'm looking for other issues, and wanted to throw this out:
Just how much of this argument is due to the merits of the sytem, and how much is due to smoldering resentment of HK's civilian marketing?
What if the Hummer were being replaced by a Porsche or BMW machine? I would hope we'd be angry that money is going overseas, without all the other issues.
I do think that HK is missing the boat by refusing to make civilian versions of their military long arms. I suspect it's a business decision, perhaps fear of American litigation. I don't think they intend to be elitist, but that's how they are percieved by some.
I agree that the XM8 looks like a plastic toy. I thought the AR looked like a plastic toy when IT came out. And I still think so. My first AR, on top of that, was a POS. I was an HK convert for years, bought their marketing, hook,line and sinker. It wasn't just that, it was that the ones I shot didn't jam, and they shot little tiny groups.
I still think, FWIW, that the various G3 clones are the sexiest looking guns around. But I can't or won't afford them. I feel the same about Porsches and Beemers.
The AR I have now, a Colt, doesn't jam, and shoots better than I can. It's still ugly, but it works for me.
To come to my point, if indeed I have one... there is more than one argument going on here.
Economics - I don't like money going overseas.
Practicality - I agree with the post about lethality. I haven't seen anything to suggest that the XM8 is any more deadly than the M16.
Esthetics - they both suck. Go with what works.
Which is the best - I can only say what works for me. I'm not military and not LEO. My Colt does the job in spades. ( so does my Buick. Up yours, elitist swine.)
The above remark about elitist swine is a JOKE. If ya got the gitas, have fun.