I've heard AF140 on home audition, almost bought them as well.
The AF140 received mixed opinions mainly due to its rather dark signature. Unless you know how to accept different tonalities (warm/dark/cold) or the signature sits comfortably 140 sound rather veiled or muffled, thick in the mids (great for long listening) Despite this, its rather detailed and has a real musical talent. The low end is rather emphasised and treble slightly rolled off giving A83 the upper hand in balance. A83 is much cleaner, brighter compared and will outclass the 140 in detail.
The story behind it was, I had AF140 for a couple of weeks and almost bought them, mainly because it was unusual, it sounded grand with most music and let me listen exactly like you said, without analyzing music. But only days after Vics A83 demo arrived and due to my preferences (which are inline with your ER4) it was all over for AF140.
If you want to be different take AF140, (but there isn't much conversation here about it, you would be one of few)
If you want an ER4 with more bass and engaging character (adding some analyzation) take A83.
Keep in mind A83 can be a little exhausting, exhilarating, over committed, far from the laid back mellow AF140 approach.