Mark,
Depending on things like upgrade sets, tracks, etc., the kits can run about the same. I have both the Tamiya H and J, and the Dragon H late smart kit. I do think the Dragon detail is finer, and should not be a prickly build as some of their earlier Mark 4s. I would not turn my nose up at the Tamiya kits, but you'll likely want to replace the tracks. The Dragon Smart kit has the Magic Tracks, so you shouldn't need to replace them.
Good luck, can't wait to see the build!