Twitter has announced user token limits for 3rd party Twitter apps which means that, one day, they'll no longer be able to accept new users. It won't be today, or tomorrow, or perhaps even for a year or more. But it will happen, and if Twitter changes things again, it could happen sooner rather than later.
So to get in and get your tokens now, and to support the developers who have devoted their time, money, sweat, tears, and blood into making better experiences than Twitter themselves were willing to or were capable of, grab one these apps now. If you want some real fun, grab all of them.