Objective stuff:

It has all of the functionality of the Sony grip, which for these camera's is pretty limited. There is a shutter, a command dial, and AEL and WB buttons. This means it will handle most of the functionality that you need for shooting. You loose access to things like ISO and drive mode that you normally have with the built in grip, but having these other controls handles most shooting needs. It has a build in place to store the A300's battery door, just like the Sony grip.

note: I obviously forgot how to use my CyberShot, the pictures are horrible, but they get the point across.

The Feel:

Part of the reason I bought this was to see if I liked having a grip on a camera or not. I was recently looking at a thread about grips at POTN, and it was obvious that there are strong opinions for and against. I don't think there is a real answer, and one just needs to use a grip to decide if they like it better or not. In my case I do. I like the feel and handling of the camera better. I don't know if a battery grip could rescue a Rebel or D40 from its tiny grip, but it certainly helps the A300 feel more solid. I've been playing with prosumer bodies lately (A700, 50D, D90) and one thing I really like about them is the more solid feel. This doesn't make the A300 feel as good as those, but it helps. The (slight) extra weight of the grip and the extra weight of the second battery add a lot to the feel of the camera.

I think this third party grip might be made off of the same mold as the Sony grip, but I expect the materials are not the same. I haven't actually used a Sony grip, but this Travor grip, despite having a great layout and being ergonomically stellar, feels CHEAP. The A300 doesn't feel plasticy, but this does. If I move up to a prosumer body, I will certainly buy an OEM grip instead of third party. But on a cheap body, it might be worth it. For 1/2 the price I get the exact same functionality, but what you lose is the solid feel. In addition, with this grip you can only use one battery at a time. I was under the impression that most battery grips allow you to pull of both batteries without having to change anything. With this one you have to pull the tray out and flip a switch to go from battery 1 to battery 2. So if you aren't interested in the second grip except for longer battery life, just carry a second battery in your pocket. It is less work to swap batteries on the A300 than to pull this tray out and flip the switch.

Deal Extreme:

A little about my experience with deal extreme. I ordered this grip more than 3 weeks ago, and only received it today. The third party battery grips for the Sony A200-350 can be found on ebay for just under $100, but deal extreme had the same one for just over $70. I figured that paying for it at dealextreme.com plus express would get it to me faster, but I was probably wrong. Deal Extreme doesn't keep any items in stock, instead they order them from the supplier when you order the item. The website says that receiving the item from the supplier takes 1-3 days. It took them almost 3 weeks to get the grip in stock, but once it was it was packed and I received it via express service in about 3 business days. I can't complain about the shipping, but I was disappointed about the wait before it shipped. It was well packed, and once they received it, the item was in my hand in days, for a very reasonable international express fee, but I was very frustrated with the wait.