I am a satellite engineer by trade, and have worked for and with DirecTV and Dish since they both launched. I can't add much to what's been said except that the difference in experiences you see here is all related to the quality of the installation. When it's "FREE" you pretty much get what you pay for. My advice: Call someone local who answers their own phone, and has been in business for a while. Ask them if they do their own installations, and what their warranty is. Do not, under any circumstances call an 800 number to order your service, the installers who show up may not even speak English, much less know what they are doing.
Get someone local and reputable who will stand behind their work, and if you have to pay a little more, it's very worth it. It's really doesn't matter where in the country you live, a good installer should be able to get you very reliable service except in the very worst weather. If you lose your signal more than a few times a year for a few moments, it's not done right.
All full CONUS (continental United States) Satellites orbit around the equator, so that the further south in the country you live, the higher in the sky the birds will appear, so if you are in FL, your dish will point up, if you're up here in northern NY, it points almost at the horizon. As long as there is a clear line of sight though, it doesn't matter for signal reception or reliability. Clear means clear though, not partially obstructed by trees or anything else. Any blockage will cause problems.
If you can help it, don't get a satellite dish installed in the winter because spring leaves can eclipse your line of sight where bare branches won't. Most installer make nothing at all if they find there is no LOS (line of sight) so they have a strong incentive to do marginal installs that may only work until the leaves come out. By that time they are long gone and couldn't care less about your problems. Once again go with a local guy who will be there in the spring if you have problems, and will stand behind his work.
The biggest problem with the whole industry is that both companies went to this 'free' model, causing them to have to get the cheapest installers possible, and while it's not really that hard, there's more to it than they want to admit, and a 3 hour class does not a competent installer make. These days if you find someone who has been in the business for more than six months your doing well, and as with anything else, experience counts.
As to which is better, Direct or Dish, I can't say, it's really all about what programing you want. From a consumers point of view they are equally reliable if installed correctly. I work on the transmit side for both, and Technically they both have their strengths and weaknesses.