Honestly tough to answer this. It's one of those things where you just have to use it for a while to realize how supportive it is of programming. All of the bundles (mostly developed by third parties) certainly helps. You can basically automate/script the application any way you like. There are bundles for different frameworks/libraries that can speed up common development tasks.
But is it better than Eclipse in terms of sophisticated language support? For a dynamic language, maybe that's not so important. But for a verbose statically typed language such as Java, it's critical.
BTW, if you have not checked out Eclipse lately, see:
I don't see it as a tool which can be compared easily. Eclipse (in my view) is more of a complete IDE. Same with Visual Studio (also superb).
Textmate is a seemingly minimalist programmer's editor. When you get into it and start hacking you start to see how much is really there. Definitely not an IDE though.
I've been using Eclipse for java development and have been very happy with it.