The gloves are off, it would seem. A particularly important update the M5000 which was, quite frankly, under-equipped compared to it's younger brother the M4000.
It's good to see the VRAM up over 20GB, however I wouldn't personally consider these cards a truly viable alternative to CPU rendering until they are cost effectively over 30GB.
Having said that, I plan on looking more closely into RedShfit over the next few weeks, to see if the out-of-core architecture can truly circumnavigate the issues associate with RAM limitations, and most importantly, whether performance in arch viz scenes is high enough to justify the inevitably time-consuming shift from VRay.
The alternative being of course just to sit on your hands for GPU's with very large amounts of RAM (as above) to come out and just use VRay RT. VRay RT is becoming more production ready with each release, and although I rarely can get all the way to final with the GPU renderer, I'm getting much closer to being able to.