let me preface with the fact that i don't own either of these knives.
i was however lucky enough to drop by gpknives today and handle a bunch of knives i had only previously seen online
to me, a ruckus and manix are a terrible comparison in size distribution (girth vs width), lock (axis vs. lockback), cost (~$50), blade length, and blade style.
for the ruckus i would really wont to compare it to the ontario retribution 1 or the big lone wolf folder.
for the manix not too much comes to mind. i would consider the military and chinook +/- benchmade afck/710, full size ritter (with regard to blade profile/solid grip), rat trap (never seen this guy in person) and maybe the mid size lone wolf. none are really good direct comparisons obviously...
based on handling the manix, i really think it fits a pretty "unique" nitch... just my 2 cents... i would really love to own BOTH!
ryan