What I thought people would comment the most about Tweetbot for Mac was actually spot on. Most people started to question the decision of Tapbots to priced Tweetbot for Mac at $20. The reason behind this is not so difficult to imagine.
Recent changes on Twitter Guidelines gave a sort of expiration date on third-party clients. It imposed a limit on the number of tokens that can be granted to those sort of apps, which means that there is a limit to the number of Twitter accounts Twitter clients can access.
In other words, if you want to make money out of your already in development Twitter client, you need to price it high. But Tapbots can get away with it for many reasons.
First the app is very well done; graphics, animations, sounds and tools are just great. Second is that you rarely spot a bug on Tweetbot and if you do, you let Tapbots know about it and it will get fixed, as long as in in their hands, and not on Twitter's.
Third, Tapbots is continuoulsy updating the apps to polish them even more, add more features and squash some bugs; you a re not paying for something that will not get better with time.
We must not forget that this is the Mac, not iOS, where we are used to see apps priced cheap.
If you are really serious about using Twitter on your Mac, Tweetbot is the answer. The official Twitter app ceased to exist, although the company is supporting Tweetdeck for Mac, which blows my mind since I can't find it very useful.