Do you feel as though you are limited by your camera right now? The A330 has all the standard features that a photographer will require. Unless you are a professional who demands the absolute best in performance I do not believe you are limited in any way.
With regards to image quality, I'm pretty sure that it is Sony that manufactures the imaging sensors that go into many of the more popular camera brands, like Nikon and Pentax. The image quality will only vary through the post-processing that is done in various ways by the individual camera brands in order to get the final jpeg image output. Sony's jpeg algorithm may not be as refined as say, Nikon, but you can always shoot in RAW format and do jpeg development yourself.
Forget about the camera brand - it means very little in actual performance. Just a couple of years ago nobody had heard of Pentax and would scorn at such an "unknown" brand. But Pentax is one of the oldest camera makers and has an impressive history. Now clubsnap loves Pentax models.
I think Sony is progressive. They've taken the plunge into interchangeable lens cameras (the NEX series), along with Samsung, Olympus and Panasonic. Canikon and Pentax still lag behind. They've even put the translucent mirror into actual practice. On this basis I would say that Sony has guts and can be depended on.
