Being a fan of 12-inch figures, I would say of course it's a good idea to get it. I don't really think your qualms about visible articulation are justified. Most of Sideshow's figures have the articulation completely covered by clothing. The only exception in the LOTR line are the feet of the hobbits (something that I think they could have handled better). When the articulation is hidden, these figures are like posable statues, which is what I love about them.
If you don't mind waiting a few weeks to get it after they first come out, getting it from a reseller will save you some money. Also, the history of the line and of Sideshow's 12-inch figures in general has shown that these will not exactly be hard to find in the future, and probably for less than Sideshow is currently selling them for, so you don't necessarily have to feel like you need to grab it this instant. I would expect them to be fairly easy to come by on the secondary market.