From personal experience and from studying photos, I think that anything that Medicom does, Sideshow does it better.
Sideshow Stormtroopers are far better than Medicom's. Sideshow's Anakin Skywalker and Luke Skywalker Jedi were better. Sideshow's Indiana Jones was far better.
Even a Hasbro OTC Stormtrooper has more presence among Sideshows than Medicom's skinny alternative. They're a far closer match to my SS Stormy.
I find Sideshow's facial sculpting to be superior to the soft, rubbery look of Medicom attempts. Sideshow's bodies may not be up to the same flexible standards, but are probably a lot more robust (though the Prometheus can have a tendency to be too flexible).
That said, I think an SS Boba will be a must have.