Hi, Steamboat! I'm a member of Indy Lightsaber Academy, in Indianapolis, and here's what I've observed -- though I'm sure some of this will reveal the biases of my instructors!
Ultrasabers and SaberForge both allow you to order parts to build your saber yourself. I think SF has a more flexible system in this regard, because you can design the saber on their site and they assemble and ship it, if that's something you'd want. However, I've heard some mixed reports of the quality of SaberForge's product -- some very good, some not so much -- and the owner of the company has a reputation for being, ahem, difficult to work with. (ILA no longer works with him, and that's all I feel comfortable saying on the matter.)
US has the advantage of very fast shipping, but I can also tell you from experience that some of their hilts are extremely bulky. I got my saber from them (a Dark Apprentice model with a Consular Green blade color), and for my Form I instruction it was perfect for my two large hands, but now that I'm working on Form II, I really need something smaller. But if you want a Darth Maul-style two-bladed staff, or a longer pike hilt for a defensive style, they're eminently suitable. Also, the community on their forums is really nice.
We've had really good luck lately with a company called Crosspoint Sabers. They're based out of Ohio. Am I allowed to post a link to their Facebook page?
