The Land Raiders are some of my favorite tanks in 40k. They're hard to kill, they've got machine spirit... and in the case of a Redeemer, you've got a pair of the most badass flamer weapons in the 41st millennium.
I could go on and on about reasons as to why Land Raiders are excellent tanks, but instead I'm going to argue for why I opted to take the Redeemer variant over the Crusader pattern.
Points wise, the Redeemer is 10 points less than the other two, so not much to argue about here. However, that extra 10 points gives me that very useful Multi melta upgrade. The real differences between the variants is transport capacity and weaponry. The Redeemer can carry 12 models, or 6 terminators compared to the 16 models or 8 terminators of the crusader. It then becomes a question as to whether the flamestorm cannons over the hurricane bolters are worth the loss of 2 terminators inside.
In my opinion? Absolutely worth it. The twin flamestorm cannons transform the Redeemer from a hard to kill transport into a hard to kill battle tank. Hurricane Bolters are just too lackluster. I get the argument from Crusader-toting players all the time, that the 24" range is just so crucial and makes the LRC much more tactically flexible. I don't buy it. I play against Crusaders all the time, and their Hurricane Bolters pretty much always amount to diddly squat vs. my marines. Flamestorm cannons? Boom, say goodbye to that entire tactical squad (or at least most of it). Even if I only fire a flamestorm once per game, they're still overwhelmingly more effective from my experience than multiple turns of Hurricane shooting.
This brings up another point I would like to make in favor of the Redeemer. The last few games I've used my Redeemer in, I've been getting weapon destroyed results on it. Every time, my opponent won't know what to take off. All the weapons are equally devastating in their own right, and losing a flamestorm cannon or assault cannon is no big deal. With a weapon or two lost, the LRR still has the potential to do some serious damage, something that can't be said about an LRC or standard LR.
Lastly, I don't use the LRR as a transport all too often. It's more of a fire magnet to take the pressure off of my more fragile (and valuable) Vindicators. The trio of hard hitting tanks will clear a path all the way to an objective with a squad or two of foot slogging marines hidden behind, and there is little an opponent can do about it when the rest of my army is supporting the advance.