Downtime sucks. In general. Tweet Attacks rocks. In general.
Putting all your eggs in one basket is a huge mistake.
Jay and his team have worked their asses off on this program to keep it up to date and solid, and the one-time fee is so reasonable. I've commented enough about my feeling about 1&1, but based on TA's track record, their statements, and their actions, they're taking the needed steps to not have this happen again in the future.
EDIT: just to add and clarify, relying solely on one tool or one method is a horrible mistake (see Yukinari84's references to the "silver bullet" that doesn't exist). TA is the best tool out there for twitter, and in turn twitter can be a very useful asset. But don't rely on any one *thing* for all your work.
Also, Jay has been very active and keeping people up to date during this nightmare, which is awesome (I can only imagine how active his team has been behind the scene trying to get things patched up). How many people who've been around for awhile have just seen a tool go tits up and never heard from the devs again?