[26 April 2010]
The other day I thought perhaps it was time to try Aquamacs again, a nice, actively maintained port of FSF Emacs to Mac OS X. I’ve been using a copy of XEmacs I compiled myself years ago, with Andrew Choi’s Carbon XEmacs patches, but recently it has accumulated some problems I don’t have the patience to diagnose.
Got Lennart Staflin’s psgml package (a major mode for SGML and XML documents) installed and compiled; this is a pre-requisite for any Emacs being habitable for me. (Why is package management such a dirty word in FSF Emacs, by the way?) And discovered that on one of my larger documents, psgml takes 50% longer in some tests (9 seconds vs 14 seconds) to parse a large document in Aquamacs than in XEmacs. In other tests, it was 9 seconds vs. 90 seconds (or so — I kept getting bored and losing count between sixty and eighty seconds).
I may not be leaving XEmacs after all (undiagnosed problems or no undiagnosed problems).
[Postscript, 7 December 2012. I did eventually move to Aquamacs, and have been very happy with it. The performance issues reported here have not recurred on the Intel CPU I’m currently using.]