Last year we purchased ProEXR and converted our Photoshop stills workflow from Single Channel EXR to Multi Channel EXR's. It's a huge improvement in productivity when your renderings include 20+ render elements that open as layers in Photoshop. Do that same rendering multiple times with varying iterations and the productivity savings keep stacking up.
No more dealing with render element paths or creating folders for every iteration because you have so many elements. Just a simple, single EXR file of your latest rendering. Yes it takes more space but if you're in a line of work where projects last a while and there are lots of iterations I suspect you'll find ProEXR a worthwhile addition.
While I'm aware Cebas PSD Manager directly creates PSD files from 3ds Max I prefer the multi-layer EXR method as its a core feature of the renderer rather than a 3rd party plugin.
Side note - the developer of ProEXR has to be one of the most responsive developers I've ever worked with. I've worked with him quite a bit to improve the performance of ProEXR (especially within AfterEffects) which I'll post about soon. He's delivered fixes / improvements in the same day - something I find incredibly valuable.