I've been contemplating a mac laptop for a while - textmate was almost what put me over the edge on my decision. Guess I can stick to Windows for a bit longer now :)
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 got a mac :) just for all the tempered souls who are waiting for leopard to come out and have persuaded themselves not to switch... (like my cofounder..shh)
I had been using Komodo for the last few months which is a nice IDE, but this looks promising.
I've tarballed the latest bundles from their repository and renamed all ":?*\\|" characters to DOS friendly characters, if you want to try out a bundle that isn't included with E. You can grab it from: http://www.bigheadlabs.com/~jason/Bundles.tar.gz
On the surface it might look like TextMate but after trying to use it for about 10 min, it fails to live up to this moniker. It doesn't do 20% of what TM does.