I like them both but I prefer the medicom stormtrooper each having their own pro's and cons. The one centimetre difference does not bother me unlike some drama queens who claim it as huge or the hands size as its in scale with the figure (really do we all have the same size hands)
Medicom:
The medicom Shadow trooper looks better with the gloss black armour.
The bodysuit looks and feels better
The stiff articulation on the medicom when moved for poses.
The armour is tight on the medicom body.
Sideshow:
The sideshow E11 blaster is the best replication for any scale figure.
The detached belt with holster and flap that has a magnetic catch.
The body parts are easily taken apart. ( you ever tried to take the helmet off a medicom sheesh)
The use of elastic to hold Armour pieces together.
These are the reasons "I" like them both won't go into the cons about them. ( Well i did shell out a Hundred clams for them both)