That's pretty uncharitable to LightTable which is doing a number of things differently. Inline evaluation, and great support for ClojureScript with a connected repl to name a few.
What was it a few years ago? I'm going to guess that whatever the answer is, it didn't have anywhere near the extension capability of either Emacs or LightTable.
A few years ago I would have gone with Sublime, and TextMate before that. I haven't tried extending LT, so I don't know how easy that is for a mere user. Both Emacs and Eclipse are very extensible, but only the former provides a smooth path to go from tweaking a few config variables and defining some macros, to writing serious extensions. I gather LT is mostly in ClojureScript (?), which suggests it's more like the former, but I would have to spend more time with it to say for sure. I played with it a bit, and it looks pretty, but it's not aimed at the projects I'm dealing with now.
