Procmail vs. Maildrop - which to use?

I need to do mail processing where I manipulate the contents of the mail or invoke a script on the receipt of email, supporting a number of email addresses as the access points. In reading through the MDA agents, procmail appears to be the standard standby, but maildrop has some following too. Wikipedia comments that anyone starting something new should consider maildrop because procmail hasn't been advanced in quite a while.

Are there any solid reasons from features or capabilities that would indicate using one of these over the other?

It is quite difficult to answer. As far as I can see, procmail is very stable and works well. It is not clear (to me) if maildrop can be integrated so easily in .forward like procmail. The good things of procmail are:

• it is based on pipes, so you can easily add filter using formail+sed+bash
• it is easy to build a yes/no filter to use with procmail (i.e. a spam processor)
• do most of the things you need
• the mailing list is still alive

On the opposite:

• procmail syntax for dynamic match is complex (the / stuff) and I have found little example
• documentation is scattered on a lot of howto. This url is good http://pm-doc.sourceforge.net/doc/ but should be edited a bit.