LoTR is a bit abstract, but it's really well-balanced and when we play there's a constant feeling of dread. I like it with two players because we slow down a little bit and then it feels a little bit more like a journey than a LoTR theme with the Knizia treatment. It's a very risk-reward type of game, and it's one I don't plan to get rid of.
Pandemic with two feels less fulfilling to me. The things that I like about Pandemic are all the things that go wrong and the strategic discussion that happens when it's not your turn. The board is changing, diseases are spreading, and it all feels very big in scale. With two players there's less of that, because less happens when it's not your turn. That being said, with four players I think Pandemic is a blast. It's mostly reigning in the chaos, and it's also one I don't play to get rid of.
Difficulty-wise we don't have a real high win/loss ration with either game. I've got at least a dozen and a half plays out of Pandemic and I don't feel burned out on it. We've played LoTR at least a dozen times, and I still enjoy that one too. Both base games are great but the LoTR game feels more complete with the Friends and Foes expansion, which as far as I know isn't available for the new FFG Silverline edition. The expansion for Pandemic is fantastic, and if you're in the mood for a versus-style Pandemic then the BioTerrorist is pretty cool variant that actually works decently with two players too.
I'd say the Pandemic base game is slightly more approachable for new players, but they're both really easy for regular gamers to grasp. Go with the one with the theme and mechanics you like best, but if you're thinking LoTR research the new Silverline edition vs the old edition with expansions before you buy.
I haven't played LoTR because it just didn't look that interesting. Pandemic has replay value I guess, but it just didn't have any lasting appeal to me. When I'm playing a co-op, I want something that stands out as an experience. Pandemic after a few plays will just turn into an abstract puzzle without much suspense, surprise, or narrative. I don't know, it just lacks that 'it' factor for me by being pretty bland. For pure co-ops, the optimal number of players doesn't really matter, so I wouldn't worry about that crap.
The only co-ops that I've found to be consistently fun after tons of plays are Arkham Horror and Space Alert. Arkham Horror has all the narrative I could ask for, and Space Alert is just such a wild mess than no game ever feels dull or scripted. In short, they create memorable experiences. Neither of these might be suitable as family games, unfortunately, depending on the age of your kids or their experience with gaming.
Yeah, looking more for something when I'm at the in-laws. AH, DotR, Ravenloft, all these types of games are great, but out of the running.
I'd say it then mostly depends on what type of people your in-laws are. My dad likes Scotland Yard and Pandemic, my mom likes Citadels and Bohnanza. They both liked Dixit, Bang, and Perudo (Liar's Dice). I don't know if I'd spring LoTR on either of them, frankly.
If complexity is an issue, Elder Sign and Forbidden Island are dead simple to teach and play. Shadows Over Camelot too, as long as the traitor understands their role.
I think that this is way better, even with the nostalgia I have for the Summer of Pandemic. The Circus rated Pandemic higher, but I think Flash Point fixes the "this shit can get real old" and "Alpha Male Dickweed" problems to a large extent.
Depends on your in-laws. LotR is a pretty gamer-y game: very intense, I usually feel pretty exhausted by the end. But I love it, and definitely prefer it over Pandemic, which is also stressful but much shorter, and your death isn't as drawn out. LotR is more epic, Pandemic more compact and casual.