The Pre's adapter is a full 1A (1000mA), anything less and it's not going to work, especially with the Touchstone. If you've been charging your phone with any adapter (with the micro USB), odds are that you were using a lesser powered one, the most common are 500mA.
This might explain your battery issues, it might not have been charging the battery correctly.
And I do believe that the Palm ones are of much higher quality than the general ones out there, but I'm not sure if there's a chip in them or not, but overall, just for the quality, I'd recommend them.
The Touchpad's adapter are 2.1A, and 5.3V, something that I've not been able to match. I did get the Touchpad's Touchstone to work with a third party 2A adapter, but the Touchpad doesn't recognize it if I plug it in directly, so there's probably a reason for that.
But back to the Touchstone, I might be wishful about it, but I find that my Pre charges faster and better using the Touchstone.
One warning... sometimes the back of the Pre can have an issue and it won't charge right. Make sure that you play with it, remove it, put it back on firmly and such... I know that mine had a faulty one, but I was lucky enough to have extra backs. But it's something I've read on other threads in here, so it does happen.