I'm not sure when you tried, but I'm using it since 2006 and although there are bugs we are steadily improving it and personally I (and many others) use it eve

I'm not sure when you tried, but I'm using it since 2006 and although there are bugs we are steadily improving it and personally I (and many others) use it everyday and do not experience any serious issue, especially in the last versions. Please realize that TeXmacs is a complex piece of software (is typesetting engine + macro language + UI interface together) so is more difficult to maintain than each piece separately.