If you've never shot an AK in 5.56 or 5.45 you're in for a treat. The recoil is even lighter than the 7.62x39 and with an AK-74 brake, the rifle hardly moves. Recoil impulse is only around 2.5 ft.-lbs. for the 5.45 round.
From what I've read, the 5.45 AKs are generally a bit more accurate than those in 7.62x39. I haven't shot mine enough to confirm this, however.
I got into the AK-74 game late, shoulda done it several years ago when the milsurp mags were ~$5 each. Oh well, at least the ammo is still cheap. Today I received 1500 rounds of Silver Bear 5.45x39 from AIM for ~$300 shipped. I decided to get the Silver Bear since my '74 is a Century NDS-2, which has an American made barrel with no chrome lining. This way I don't need to clean it the same day I shoot it, as I would with milsurp 7N6 (though I already had a case of that on hand).
The NDS-2s have a generally good reputation as cheap blasters. They are built from a mix of Bulgarian and American parts. They use a Tapco G2 fire control group, which is good. The US-made furniture they come with sucks, though. The butt doesn't have enough drop and some guys have reported melting the handguards in rapid fire. I replaced the furniture on mine with a set of K-Var OD plastic, which has a stainless steel heatshield in the lower handguard. It looks, feels, and performs a lot better than the Century crap.