Dan21, I look forward to seeing how other Astak owners reply to your question.
I haven't purchased one yet, but when I do, it will be the Astak Pocket Pro. I considered both the Astak and the Sony 300. Here are my reasons for going with Astak:
1. The customer service! Just from reading here on the forums, the customer service is great! From what I can see, Robertb does a really good job taking care of people and making sure their concerns are addressed. With Sony if there is a problem, I think you have to call a call center in India (not sure on this, just what I've read somewhere) and my limited experience with overseas customer service has not been good.
2. The features of the Astak seem much better than the Sony! I don't think I'll use the mp3 feature as I have an mp3 player I like pretty well, and I want to conserve the battery life. But I like the fact it has expandable storage, and it supports so many formats! I doubt I'll ever use all of them, and half of them I'm not even sure what they are.
But it just seems nice to have the features.
3. The look and feel... I tried both out in stores, and I really preferred the look and feel of the Astak. I like the softer case, as opposed to Sony's metal casing. Also, the Astak is a bit smaller, even though the screens are the same size. It's not much of a size difference, but just enough that the Astak will fit in my purse, whereas the Sony will not.
4. The accessories... The Astak comes with a case, headphones (which I'm not sure I'd really use), and a charger. The Sony doesn't come with any of those. The charger was the real selling point to me... you can charge both with your computer and USB cable, but I've just got a netbook, and I don't want to have to use that to charge my reader. With Sony, if you want the charger to charge it in the wall (is that called an A/C adapter? I'm really kind of ignorant in all the computer terms), you have to pay an extra $30.
So, that's why I've chosen Astak over Sony. You can take all this with a grain of salt, since I don't actually have one.
But I'm hoping to be able to purchase it within the next month or two. I just have to save a little while longer. And as I said, I'm anxious to see how other users answer your question!
Good luck in finding the perfect ereader!