great observation gabe...yes it does look better going straight to your set. here is why; the signal you're picking up with your antenna
ota is coming straight from your studios in an uncompressed form. that is true hd video, as well as pure digital audio signal getting to your tuner.
i am a technician with one of the country's larger cable companies, and i am also a subscriber to directv. i have high-end audio/video equipment in my home and i closely monitor all possible types of high definition broadcasts.
first, just let me get this out of the way...a 1080p tv and a blu ray disc is just about unbeatable! anyone that doesn't have this yet needs it!
as for cable/satellite/ota broadcasts are concerned, the ota, uncompressed signal is best. however, you do need to optimize the signal reception and there are a number of factors that come into play as to how to acheive this. such factors are the ant. you are using, as well as the location of your home in proximity to the broadcast towers, to the layout of land and buildings surrounding your home. i have the high-end outdoor antenna that works just fine, and i have also tried an array of indoor antenna's, both non-amplified and amplified. what worked for me was starting cheap and trying them out to see what worked best. your tv tuner will also play a role in how well you pick up ota broadcasts also. with my newest television, the ota antenna that i am most pleased with is an indoormodel with a $49. price tag. it is the Phillips MANT510. it is the most used at this point. so just start cheap and see how lucky you get.
as for cable hd signal, i have to say it is very good. or at least from my company it is. but it is a compressed signal. we get the signals from the broadcasters in an uncompressed format, but it has to be compressed for us to send it out through the cable plant. however, if you've got a tight cable company in your area, and the last technician at your home made sure your home was clean (undamaged shielded cable, proper fittings, tight connections, no ingress/egress, proper levels and values) then you're really in for a treat. the difference you will see is mostly heard. the audio won't be as crisp, atlthough you will still get what is being broadcast. and cable companies have optical audio output and HDMI output set tops. but your run-ins with tiling and freeze frame and rainbow effect will be almost non-existent. it is a pure joy. well worth having and most cable operators now have all locals in HD as well as your major sports and movie networks in HD.
as for satellite....this is actually my least favorite of the three.
audio from satellite is almost always better than the other two sources. but, seeing as directv is not a studio themselves, i would have to think that they have to degrade the source that they are receiving in order to get it to us. how many times, i really don't know. i know they advertise a lot more HD than cable, and they are telling the truth. they have a lot of HD channels. but in reality, about half of them don't look as good as some cable companies' digital broadcasts. but, this is just my opinion, and i try to be as unbiased as i can be. i actually let the directv guy park in my front yard! with my cable truck in front of my house.
so, take this and run with it. i hope it helps some of you to find what you're looking for. and trust me, when you get it you will know it....and you will love it!
one more thing before i go...a good place to start as far as determining how your house sits and the type of signal you should be receiving in your area, go to solidsignal.com. under antenna tech help, click on HDTV channel lists. from there you will be able to pick your immediate area or an area very close to yours. you can get detailed maps that display your homes location and the proximity to your local towers, including direction, layout, obstructions, etc.
and it will suggest types of and strength of ota antenna's for you to consider.