I have used both the tank with spiral reel for inversion, and the Expert Drum for 4x5. Both work ok, but the Expert Drum is by far the easiest. It is a lot more expensive, however, and the drums are getting harder to find.
One of the best investments I made for my darkroom was spending $225 for a 3010 Expert Drum and another $25 on a hand roller base. The setup had nearly paid for itself by the end of a 50-sheet box of C-41 film, by eliminating $4 per sheet lab fees. And all my classmates used it as well. I highly recommend these, especially if shooting color.
"Truth and love are my law and worship. Form and conscience are my manifestation and guide. Nature and peace are my shelter and companions. Order is my attitude. Beauty and perfection are my attack."