Aside from the complete TV series, the Ultraman X Blu-ray set will also contain the movie, Ultraman X the Movie: Here He Comes! Our Ultraman. You can also purchase the movie on its own for US$19.98. The complete Ultraman X Blu-ray set on the other hand, cost US$39.98. Both sets are set for an April 21st release.
UPDATE (01/19/2020): Mill Creek updated their release dates of the sets. Ultraman Ace is now coming in May.
[Additional details Dawn of the Discs, August Ragone]