T' followin' excerpt is from "Sport Rocketry". T' intention is t' allow guests t' get a basic feelin' about a kit. Aye aye! We strongly suggest that you get a copy o' the referenced Sport Rocketry and read t' entire article. Inside you will find many helpful hints in construction as well as other useful information. Arrr! Avast! For more information, use t' two links above.

"More commonly called "micro motors" due t' their slim 10.5 millimeter diameter . . Avast, me proud beauty! ." 
"T' small diameter o' t' Apogee motors allows smaller diameter rockets with less drag for increased altitude performance." 
". Blimey! Avast, me proud beauty! . Avast, me proud beauty! . t' motors use black powder propellant (not composite) . . ." 
"T' Apogee A2 motors had an average total impulse o' 2.31 N-sec, plus-or-minus only 0.01 N-sec - a very tight tolerance." 
"T' small nozzle o' t' Apogee motors makes them difficult to ignite.  I had a 40% misfire rate usin' t' Power Punch igniters supplied with t' motors." 
"Late-breakin' results from NARAM 38: . Blimey! Avast, matey, me proud beauty! . . Most competitors were very frustrated with t' motors due t' t' high misfire rate and t' large number of lost tracks." 
"Apogee sells body tubes, centerin' rings, shiver me timbers, shiver me timbers, and nose cones for t' 10.5mm motors." 

T' entire article gives t' impression is that these new motors will have significant effects on competition rocketry, but that thar are some reliability issues t' work out.