Gamasutra recently featured an article I wrote on play-testing of a game during development. It was pretty much from the heart and written a couple of weeks ago just after I got Space Bot Alpha submitted in to the App Store.
The key insights from it are first that player testing is about the most important thing we can do for our game development: its like the over-the-horizon radar that is going to spot that iceberg in time, its the crystal ball that will tell me if my game is going to be a hit with players or be perceived as a bug-riddled flop. Thus its important to do it throughout the development of the game, not just near the end.
Second insight is that we don't want to do it. Its painful. Its personally challenging, and its challenging to be someone receiving feedback on something that is a creative work. But those are things we have to get over as game developers if we don't want to do all we can to avoid being surprised by a bad reception on release. Its not a universal panacea for bad launch feedback, buts one of the most important things we can do on that count.
Space Bot Alpha is out on the App Store this coming Wednesday (Australia time) and I know that there is plenty more that could have been done to make it better. But as an Indie time is always the constraint. You have to ship. Having said that I think the testing I got from players who came in to River City Labs and gave their time was absolutely critical, and for my next game I'm going to work even harder to make sure I get that testing done early.