beast you were killing me with the o.p. :-)
i suspect the reason that martysubs became a hit is severalfold:
1. designed to get the max performance out of the 18ho/si18ht drivers which are themselves great values
2. hit the sweet spot for tuning for home theater for most folks
3. offer among the most bass for the least money
4. simplified build using handi-panels required only a minimum amount of cutting
5. a plan of attack that most folks could follow
6. lots of folks all building the same thing (more or less), so ideas could be shared with respect to construction, driver, amp, etc.
edit: must add #7
. the guys who took the lead, built the first few, documented the builds in excruciating detail, and measured the performance...mhutchins, wormraper, [more later] and later chaluga who pretty much led the martycube charge.
whereas with "ported sub diy", someone has to try to figure it all out from scratch. nothing about each aspect is particularly difficult, but for guys who just show up and want to get something going, the plan, performance, and people (all doing the same thing) really helps.
i've mentioned it a few times, but several years ago, member neo dan pretty much did the same thing (though it was never my intention to copy) with his "easy button" series of subwoofers. for a while, everything around here was "easy button this" or "easy button that"
i never really understood why, but i suspect we may have some ideas such as those mentioned above.
and yes, the volume of discussion in pm's may even be greater than that on the public forum.
was it worth it? it sure was...and then some!