First, I learned a long time ago that its impossible to make qualified judgements on the things mentioned above based on STB output as it varies so much from STB to STB, even with the same service, whether it be D* or E*. Then take in the differences of DVI vs YPbPr etc and you do not know where the differences you are seeing come from. Comparing different STBs from different services - forget about it - too many variables in the mix.
I have both of these from the elementals and when I have some time intend to sit down and watch them both from the transport stream and really compare the differences with the stb connector and muxers out of the circuit - thus I won't enter the fray of how it looked until then.
I would say that the rate E* is giving it would work well ok with MPEG4, but not MPEG2.
I am working with the head of the NOC at the local cable company to find out the real bitrate UHD is delivering off the bird which will be very telling - as UHD has never looked good from any source.