The deco is making the lifeforms sounds so good (a bit of a floating ambient vibe) and the heat is processing the Rytm. I think the heat is great for drums! It makes for instance the tt606 sound like a beast. When I just got the heat i used it on the master out, but I couldnt find the right setting to make it sound awesome. For a liveset its great but not in the studio. So I use it voor drums and basses.
As for comparison Deco/Heat is not really the case. They are totally different. At first I thought it was overkill to have both but they sound so differently. The deco is also a pretty good slapbackdelay and can make your synth sound wide like a chorus. The Heat does the saturation part much better and has presets... so I couldnt choose and kept both and use both...
I totally love reverb! I use it a lot, sometimes a bit to much. I dont like the reverb in the OT though, so I have to get me a strymon blue sky or eventide space... for now the reverb on the A4 is pretty good!
Thanks for listening and comment, appriciate it!