I've tried several alternatives. Those include Hootsuite, Seesmic, and even Yoono. Between crashes, lack of real-time Tweet updates, and quirky features, none of these seem to be an effective replacement.
Then I stumbled upon the Australian Twitter client called MetroTwit. I have been using it for some time, and it hasn't crashed, and it has provided some of the same features that I once admired in TweetDeck.
MetroTwit is available in a free version that includes advertisements (You can decide which stream displays these) and support for only one account. It is also available with a paid version that includes multi-account support and no advertisements for less than 20 dollars. So far, MetroTwit has been able to deliver for me what the new TweetDeck fails to do. Download and try MetroTwit here. It might be a reliable alternative to TweetDeck.