Compare DISH to Direct
First, I would recommend running the cable directly to your digital televisions and scanning for digital channels. Those that contain a QAM tuner should provide you with your locals in HD.
Second, the quality of the installation will determine the quality of the performance of your system. Everything from reliability to picture quality is contained in the details of the installation.
So, if you have no problems with your current provider, you might want to stick with them.
If you really are interested in lowering cost, I would suggest Dish Network. As far as quality goes, when installed correctly, Dish has some of the best picture available. I also prefer the "user friendliness" of the remotes, program guide, and the DVRs. The drawback is that (like the rest of the providers) the emphasis is on speed of installation vs. quality of installation, and you may have some issues.
Changing channels and surfing times are somewhat variable. They can vary from "WOW" to "what is going on here?" Slower channel changes occur in systems that need to have the dish peaked or are losing signal quality due to high noise in the system.