I've got the MKIII coming from DAC to amp. Why ? Good reviews and was in the price bracket my chosen kit dealer told me to pick from. Sadly I've missed out on HiFi for many years so can't compare it to any other cable at all. Except 5 blind tests with a beach towel covering my 16 year old daughter and all my kit , while she swapped the supplied RCA's with the Atlas. I picked the Atlas every time. No contest. Einstien and Hawkin could turn up and tell me I'm hearing things , expectation bias blah blah blah, but I'd tell them the same. I know the kit sounded better with the atlas.
Not much point in posting about it as I can't help the OP out re MKII v MKIII. Other than to say that it feels good quality, looks good quality but whether or not it is making a positive or negative difference as opposed to MKII or any similar priced connect I couldn't say. Others can argue about does it / doesn't it .
But sometimes just thinking that it does, even if it probably doesn't, can make you happy and keep your interest going. Mrs Tech bought a frock for a wedding the other day. She thinks it makes her bum look smaller. It doesn't but she thinks it does and therefore is wery happy with her purchase. So I'd wager is the owner of the small shop she gave the £200 to. Same applies to HiFi cables imo. Money stays in the HiFi world, more manufacturers and retailers survive and we get better products no ?