I can't tell you anything about the Pansat or the Merc, but I do have about 6 months experience with the Coolsat 6000. I regularly view PBS with AC-3 audio through a 5.1 surround sound system with no problems at all. Also, while experimenting with C-Band I have seen a Japanese station but can't give any details. I was quite amazed when the newscaster, before starting to read the news, bowed very deeply to the audience. I thought he was going to take a nap first. This, I assume, is Japanese custom.
The upside of the Coolsat is that it works consistently and well, seems to have lots of memory and has a fairly intuitive menu system. Mostly it is a reliable dish mover and rock solid reliable once tuned and the channel selected.
The downside of my Coolsat is that the universal remote is not good. It can be a frustrating experience changing channel. Also Coolsat does not update its software regularly, the Fortec I understand is much better at this. Occasionally my Coolsat will freeze during a blind scan which is inconvenient, always on the same satellites, but only a few. Mostly blind scans work fine. And, as posted elsewhere, I have yet to figure out what they mean by a favourite. Picture breaks up at about 63% signal quality.
YMMV.