Quoted from iepinball:

Nope, I never completed Battle of Five Armies nor played all 31 modes in a single game. After my first day with the game I knew I had to set it up more difficult than factory to keep it fresh as 45+ minute games on it were going to wear thin, otherwise I think I may have sold it within weeks.
As ironic as this is (I'll get to it later) the bit that's missing for me is a sense of accomplishment. Yes, I get a piece of the Arkenstone when I complete a mode but it doesn't mean enough. Perhaps a bonus when I complete a second mode before "consuming" that inital piece on an Arkenstone mode? Perhaps additional scoring during the next Arkenstone mode? Perhaps increased mode scores based on number of completed modes before cashing in the Arkenstone mode? Scoring is very linear until you get to the later Arkenstone modes, and that's not necessarily a bad thing, but it becomes a grind. Yes, you can get large points grinding away at the spinner or building up Feast Frenzy values, and more, but I'm assuming there's more in store for scoring as there's a "Super-X" insert instead of a "2x Playfield" insert. Leads me to believe Keith had more originally planned there.
The one thing that kept me coming back to play was reaching Battle of Five Armies and playing through the 3rd stage in that. EASILY my favorite bit in the entire game. For whatever reason the music and speech work SO DAMN WELL during that mode, and the objective feels so different from anything else in the game. After that round though it's back to slaughtering beasts, which while very much thematically correct, unfortunately wears thin by that point.
Back to the ironic part [don't hate me Keith]...I recall reading that Keith was going to build Hobbit into a proper mode game after the lackluster initial release of Stern's Star Trek, and I'm paraphrasing here, to "show Stern how to properly build a game with a lot of modes" or something along those lines [wish I could reference this right now]. I think most people would agree that the medals system added a sense-of-accomplishment into Star Trek, and it's what's missing here now. I know it's been said over and over, but there's little-to-no urgency to completing the modes, and only a slight sense of accomplishment when a mode is completed. The feeder points / mode bonuses are not enough IMO.
All that said, I do still enjoy the game, and my son is mad at me for selling it. The theme integration is by far the best around. BY FAR. Nothing else compares. I'll still play it when I see it out and about, and hope someone is brave enough to use it in a large tournament some day. It CAN be made to play extremely difficult as I found while experimenting with various outlane configurations.