Personally I'd look at a few more options. I don't know much about DS AR15s, I don't hear any reputable things about them though. I don't know much about Spike's Tactical but they make supposedly Mil Spec rifles for around $850 to $875. There's also Bravo Company, they make great stuff.
As far as AKs go, I wouldn't limit myself to Arsenal. They're great guns but frankly they're expensive for what they are.
A lot of people will bad mouth Century guns till their mouths are dry...........and most of it is warranted. But you can still get a quality AK from most any manufacturer if you know what to look for.
here's my buyer's guide I compiled from AK shopping over the years. Sorry for some of the mishaps on here, a Moderator on the site edited it without consulting me.
http://www.zombiesurvivalwiki.com/page/Oldannyboy%27s+AK+Buyers%27+Guide.
If you follow that guide to insure quality you can get a good rifle from most companies. A few make's I'd suggest are the Norinco Mak 90s (With a square cut receiver) the Egyptian Maadi is a great rifle too, those are the two AKs I have the most experience with.
As far as ARs go, you can consult someone who knows a bit more about them and build one yourself for less than what you'd pay for a regular Mil Spec rifle. A lot of people I know consider the AR to be legos for adults.
