18 months is a long time these days. I would suggest that you retry your tests as I was convinced into using Apache2 by an ex colleague of mine who said much the same as you have, but followed it with (and I paraphrase) "We now have Apache2 running significantly quicker"

From my experience (which does not compare like for like, so it is somewhat subjective) Apache2 with mod_perl2 is quicker and more robust than previous versions.