I think part of it comes from Emacs running as one process, so things like Gnus that run periodically can make everything seem to freeze. Firefox does this a lot, as well, and it seems to be the new program that people criticize for being slow and bloated.

It's not slow as such, but interface freezes (like when you move a window and stuff under it doesn't redraw) have a disproportionately large impact on how slow programs seem to users. You can do relatively heavyweight, long-running operations without people even noticing as long as you do them in the background and don't make the interface stall out.

I'm referring more to startup time than I am responsiveness. Emacs has only ever been "sluggish" when I've used it on a system with little memory.

I have the same problem. Startup time is over a second on some modern systems. There is some good advice on how to avoid this on Stack Overflow:

http://stackoverflow.com/questions/778716/how-can-i-make-ema...

Haha. You must be missing a ton of cool extensions. My startup time is like 10 seconds. I could certainly work hard to bring it down, but who cares? I never turn off emacs or my computer.

I used to live in emacs, so the startup time was a one-time penalty in the morning. All subsequent interactions were opening new buffers from within that one instance. (This was the X11 version of the interface, not the one that runs inside an xterm.) I loved it. Eventually I weened myself off of emacs because I felt that I needed to become intimate with one of the fancier IDEs, a move that I do not regret.

What IDE did you switch to? Eclipse?

NetBeans, using the GWT4NB plugin for a GWT-based project. It's funny you should ask, as I've started looking, longingly, over at the better GWT support in the Eclipse world. (Google writes the plugin for Eclipse, so it's a well-worn path...GWT4NB is a small, volunteer effort with no official support from anywhere.)

It's sluggish on Cygwin. I guess, though, it's not Emacs' fault.

I gave up with the Cygwin version and switched to the native port (http://ftp.gnu.org/pub/gnu/emacs/windows/). Some Cygwin integration is supported by adding to .emacs:

  (require 'cygwin-mount)
  (setq cygwin-mount-cygwin-bin-directory "C:/cygwin/bin")
  (cygwin-mount-activate)

And I use the following alias to open files directly from bash:

  alias emacs='D:/tools/emacs-22.3/bin/emacsclient.exe --no-wait --alternate-editor=D:/tools/emacs-22.3/bin/runemacs.exe'

Man, if my D: drive had emacs installed on it, it would be a :D drive.

With the kind of sluggishness we are adopted to these days with firefox and network responses; I think Emacs is definitely is not sluggish.

I started using Linux on a 386 with 4 megs of memory, and Emacs was definitely slow on that machine, so I used jed. I think most people use faster computers these days, though:-)