I got a great deal on the A7 so figured might as well give it a try (as I really enjoyed the 35 and 55 FE's so much on the A7r) and low and behold, ended up really liking the 7.
The shutter lag is a lot less, the PDAF works well, and for my typical needs, the resolution is fine. The R was always pretty darn demanding of technique and for handheld shooting while out walking and such, I often wasn't really able to take full advantage of what it had to offer. Fantastic with good technique, ie; support in my case as I'm very unsteady, but overall for the way I shoot, can't really say I'm giving up much.
I may pick up an R again, provided I come across a used one a can't turn down price, for landscape work, but for the $1100 (I think it was) I paid for my 7, I'm really pleased. Way more than I was with the $2300 R when I bought it new.