Just got Voom last week or so.
Local HD channels are included, but what you get is an HD antenna along with your dish. Reception depends on your local reception availability. I've had few problems, but I have enormous trees in my front and back yards so if you have clear line of sight and/or no obstructions nearby you may never notice anything.
Satellite-wise, I've had some interesting weather around here lately so I can tell you that when satellite signal strength goes under 70% you're SOL. I don't know if that means anything to you but it can't hurt to tell you.
As for the HD channels it's sort of like cable when it first came out. Lots of crappy movies and some good content spattered about. Discovery HD kicks ass, as does PBS HD (which is a local channel for me). Voom has about 15 self promoted channels and plays many bad to passable shows on them. I do like the music stations at the end of the channel spectrum, it's like that satellite radio thing. Spartan? I can't remember the name.
For some reason for me SciFi channel is completely sporadic reception-wise. Not that they're any good anymore, but it's annoying. Locally I get more than one channel for the local stations, either their radar or still cams about town. It's cool enough to mention
You might get the same sort of thing.
It seems to me that their satellite is low in the sky so if there is lots of weather or clouds in the way the reception gets pretty bad. A few million tons of water refracting microwave signals will do that. I know as soon as there is a blizzard here my reception will die for sure. If you live in Seattle or a very rainy place I doubt you want Voom. I live in MI (where it's almost as cloudy) and I feel like I'm on the edge of acceptability.
Sound is great. My TV has good speakers, but the box has both optical and coax 5.1 ports. I hooked it into my receiver and it's as good as any DVD.
Hope that helps. I like Voom a lot, but I haven't had cable for 3 years since I moved into my house. I'm cheap like that.
One more thing, there's a setting for the non-HD display to squish the picture to 4:3 or stretch it out, I suggest 4:3 mode.