I think I'm going to post a few DCC tutorials on some items I'm working on...maybe they can help others in the market to learn more about DCC and easy it is to actually use...
Below is a chart of decoders that I'm vaguely familiar with at least in hearing, some more-so in actual usage on my own locomotives. I have not extensively used any accessory or lighting decoders at this time.
This list is also not the end-all be-all of decoders for O-scale, again just decoders that I've heard of being used in O-scale. Some of the other columns are to help compare price, current ratings, etc. Prices can vary depending on who you buy from. Shop around. More detailed technical specs on all of these decoders can be found if you Google the product name with the manufacturer name.
(Click on chart for full-size.)