After looking at the prices of a genuine Canon BG-E9 battery grip, I did a bunch of research into various options. Most of my research said that the MeiKe brand third-party grips were among the better choices. Here are my initial impressions after having it for a couple days:
-The grip fits well, very tight with no looseness or wobbling.
-The grip seems to function as it should, for the most part (see below).
-The shutter button feels a little different than the 60D shutter button -- it takes a slightly longer travel to get a half-press, and a full-press requires a little less force and has a less distinct click than the one on the body. Not a big deal.
The not so good:
-The appearance and texture of the plastic and rubber don't really match the Canon stuff. The plastic is a little bit shinier and is a very slightly different shade of black. The rubber, on the other hand, is less shiny, with a less-pronounced texture, but is actually softer and grippier than the Canon rubber.
-The fit and finish is, predictably, not as good -- the rubber inserts don't fit quite as precisely as the rubber on the body, and in some spots there's a tiny amount of glue visible (though not enough to come over the rubber or the external plastic).
-The duplicate main control dial on the grip is stiffer and harder to turn than the one on the body, and has a different texture on the knob that's a little slipperier for your finger.
-When the battery readout works (see below), it reads both batteries as having the same number of shots taken even if they originally had different numbers (for example, if I put in batteries that, when read individually by the camera, had 31 and 34 shots taken, when I bring up the battery info screen on the camera they both read as having 34 shots taken)
-There's something a little flaky in the connections between the grip and the body. For example, when I first installed the grip, the camera could not read the battery's charge information. After removing and reinstalling the grip, it seemed to work fine -- for one of the batteries. Removing and reinstalling led to the initial problem again. After a couple more cycles, it got to a point where it could read the charge state of both batteries in the grip. This is probably not a big deal if you plan on installing the grip and leaving it there for long periods of time -- just get it in a working state and leave it. But if you plan on adding/removing the grip often, for different shooting situations, say, it could get frustrating. This flakiness only seems to affect the battery charge information, not the other functionality of the grip (providing power or the use of the vertical controls).
-Haven't used the AA battery tray. Based on other reviews I'm sure it will work fine.
-Long-term durability -- we'll see.
Overall, I think the good outweighs the bad at this price. I think you can't go wrong as long as you're not expecting perfection. If you want that, spend 4-5x as much and get the Canon grip.