Played LoTRO a fair bit some time ago. My experience is that it's entertaining for a while but it's a huge grind and expensive to box if you want a full fellowship. You're looking at something like $150 USD per account to unlock all expansion content and then another $15 USD per month per account if you want VIP benefits.

There's also the issue with the way the client and plugins work in LoTRO. It's worse than vanilla WoW. You can't effectively track DoT's or debuffs on enemy targets, there's no [nochanneling] option for channeled spells and the way the spell queue (that can't be disabled) works is that if you push another ability too quickly it overwrites the previous cast so classes with complex rotations like wardens or loremasters are pretty difficult to box effectively. It's easy enough at low level but when you start doing challenging content with enrage timers and mechanics that will wipe you quickly if not dealt with properly the lack of functionality becomes a problem.

Also, just as a heads up before you invest too much time, you'll have a hard time with 3 captains as you level up. They're great tanks and have amazing group buffs that enhance the rest of the fellowships damage but their personal DPS is extremely poor and they have almost no AoE damage.

LoTRO has fairly poor class balance. If you want a DPS character at end-game the only real option is hunter. Support classes and tanks deal around 20,000 DPS, all of the other DPS classes are anywhere from 35,000-80,000 with RK being at the top end of the other DPS classes. Even a poorly played hunter with average gear can deal 75,000+ and a well played hunter in raid tier can parse 120,000+. 3 Captains will be doing half the damage of a single hunter at end-game and actually be less survivable due to being stacked and dealing with cleaves, GTAE boss skills, etc. You'll hit enrage timers on any end-game instance.