Yep, the threading may be inferior, but we feel that mod_aolsever goes a long way to helping promote adoption of (open)ACS, since apache is vastly more popular than AOLserver.
Of course, I wouldn't recommend that anyone who plans to an ultra high-volume site use Apache/mod_aolserver over AOLserver, if given a choice. However, this is a very small subset of potential OpenACS users.
Providing alternatives to AOLserver that promote adoption is, IMO, useful.
(BTW -- apache 2.0 looks like it's going to be a solid performer.. when the major bugs are worked out.)
