I was in your dilemma about a year and change ago, was a very hard decision. Decided between these 3 machines you listed. In the end, I went with tspp. Lotr seemed great to me with the rules and neat toys, and I don't mind the wood chopping aspect to the rules. Sm was the 3rd place pin for me because I've never played one before, but I do regret not considering this pin because I feel like I need a pin with gratifying shots and this seems to have it more than the three. Tspp is great, very deep but you choose what way you wanna take the game unlike lotr where the goal is Valinor. Tspp has so many wizard modes you can choose from and most are achievable. Just the right amount of difficulty in my book. Find a nice tspp and you can't go wrong. It's a blast every time. Not to mention one of the best upper pf's in pinball next to the shadows battlefield (owned that one too). Lotr, great pin, it deserves all the praise it gets but I can def see that getting old in my 2 pin only collection. Tspp all the way, theme sucks but gameplay rules, and compliments my totan.
Theme on these pins are a big minus for me as I was never really into any of them, except for sm as a kid but the vault edition isn't well done in my eyes. The art isn't to my liking and the callouts are awful. Gameplay is great but that other stuff did it in for me.
Sorry, big rant.