Valhalla Room vs IK CSR

Both are great reverbs.

Valhalla's UI is a bit more intuitive to me.

If 64bit is important NOW, I'd say get Valhalla. If you can wait for CSR to become 64bit (which they have been promising for about ayear now) then it's a dollar cheaper.

I use Valhalla quite a bit (I'm 64bit all the way. Freddie would be proud.) but when CSR goes 64bit I may use it some more.

Don't have both of them. I have 2 commercial 3rd party reverbs that are both outstanding in Wizooverb and Vahalla Room. In my opinion I never need nor do I want another reverb. I only use Valhalla Room and Sonitus for a drum room bus, wizooverb is great, but I don't need it. Recently, I auditioned Valhalla Room for that Sonitus drum bus slot and I could easily move Sonitus out of the picture. Valhalla room is lush and smooth whether you're going for a hall, room, or for what I use it for the most - plate reverb. 

It is continually updated and the developer is very active on various forums. The new darker verbs are fantastic. I find that in a lot if situations, I have trouble dialing in a sound that I don't like. There is also a nice community that offers great sounding presets. A couple of mine made the list a few versions ago. Hopefully for you, they both work equally well and you're end up in a can't lose situation. You can demo Valhalla Room for 30 days I believe. Can you also demo IK CSR? If so, you should be in a good situation to make a solid choice.

CSR is like a workhorse reverb. It needs a good old tweak too. It's pretty similar to the more expensive Breverb. I'd say if you had nothing else then it's a good starter and at a great price. There's been a swing towards the more 'lush' reverbs (for want of a better dscription) recently. Reading around and seeing people who know what they are doing, they seem to be able to get any reverb package to sound like the next one. In short, what do you already own? It may be enough already.

CSR has become my go to reverb for the most part. I still use the Focusrite Scarlett reverb plug in too but I really really like CSR

CSR is my go to. I'm full on 64 bit but it works perfectly through jBridge.

I have Pantheon and Perfect Space as well as the Sonitus reverb and earlier Cakewlk fx reverb (DX) but to be honest I find CSR to be all I need.