My experience with different models is somewhat limited, but I switched from Palm to an HP iPaq 1940, and I'm happy with it. If you don't care about WiFi, the 1940 is an even better option - I have a WiFi card in mine that takes up its SD slot. In fact, if you don't care about SDIO cards at all, you could probably get by with just a 1910, although it has less RAM.
These models are both discontinued, but they are widely available on eBay at good prices.
For PPC stability, read my articles on this site about moving from Palm to PPC. Bottom line is that both platforms are equally stable with standard software loads. You can destabilize either with poor or test software.
The Dell Axim series are also a nice product line. They are generally small and fit in your hand well. Axims also tend to be $100 or more less than comparable HP devices for the same capability. Your best bet is to read the reviews here and then cruise the retail outlets and try different models until you find something that you like.