The normal shutter sound is, I believe quieter than the 7D, although I've not done a direct comparison (correction. I've just done a comparison and the 7DII normal shutter is quieter than the 7D). The 'silent' shutter is very quiet - almost like the sound you can dial into a bridge camera to let you know a picture has been taken.
I was using Auto ISO with TV for some of my shots in poor light yesterday. If I'd had my wits about me this morning I'd have rolled the shutter speed using the top dial to 1/2000 or even 1/2500 for the swan, but I'd forgotten I'd changed it to 1/1600 for the rail and some other less reflective stuff.
I tried to do a noise comparison with the two cameras yesterday morning in poor light, but the subject I chose was a bad one - a tree trunk. Unfortunately when I got home I realised that the trunk had too much texture to be much use for the purpose, so I'll maybe use a brick wall or something else plain and try again.
What was interesting in that experiment was that at all ISOs that I used (400, 800, 1600, 3200 and 6400), the 7DII gave lighter images than the 7D. I don't know if this is normal to the sensors, or if it was just my camera, but all photos were taken on AV auto with the same aperture, tripod mounted with the lens fixed on a particular blemish on the bark. I changed the camera bodies over without disturbing the lens. (edit, I've just pulled a couple of the shots from the recycle bin and the 7D opted for 1/400 sec, while the 7D chose 1/500. Both in similar light and both in this example at F5.6 ISO 3200 (see below) The same thing happened at all other ISOs).
I believe you can add EV compensation in manual, but I've not tried it. I tend just to adjust the shutter speed or ISO to get the same effect. I can do the former without moving my eye from the viewfinder.