To begin with Aaron is kindof a private guy so that has something to do with it.  Second he is quite busy.  You mention AOW (which is a GREAT game BTW) but they have a full time staff of folks who do this.  Shrapnel has only one full time employee and so does Malfador.   Everyone involved either works off of percentages or are volunteers.  I know Aaron gets a ton of email from folks and works closely with his own beta testers and our testers as well as the numerous folks who email him privately.
Myself I can't post as often as I like because my daily routine consists of answering somewhere close to 100-200 emails, handling Shapnel business and helping our developers and testing, and then checking out the double digit forums and newsGroups I check every day.  Many times I don't even get a chance to read every thread because of that.
But to answer your question I think it is pretty good (as far as support goes).  I have been involved with the gaming industry in one way or the other for 5 or more years now and I have seen the great support guys like Tiller, Reynolds, Grigsby, Moylan, Koger and several other I am forgetting.  When I recruit a developer I try to find someone who has that level of commitment to their customers and in almost every case that has been the case.
You may want a more personal response on the board bu take it from me in his own way of doing things Aaron is very responsive  

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Sarge is coming...
Richard Arnesen
Director of Covert Ops
Shrapnel Games
http://www.shrapnelgames.com