As far as the product goes, they both provide pretty much the same product.
As far as sales pitches go DirecTV is much higher pressure and I've heard much more misinformation and B.S. out of them. They've also had a higher number of complaints from clients about deceptive business practices and fine print in their contracts.
Dish Network also has some equipment offerings that DirecTV does not. DirecTV only has single tuner receivers. Dish has some dual tuner receivers (two TVs off of one receiver or Picture in Picture on one TV). Their new system, the "Hopper" allows whole house DVR viewing on multiple sets.
You would need to compare the package pricing depending on your wants / needs.
I deal with both Dish and Direct at both of the TV stations for which I am responsible. Dish is easier to deal with and usually more on top of things.
Well Directv will lie to you big time and i mean big time just do a you tube search Directv sucks you see how they are plus there boxes are complete junk and sluggish don't be fooled into there crap
now im not going to say dish network don't have there problems but they don't have near the problems directv they have muich better boxes now and there dvr is pretty cool if your thinking of getting dish or dtv go with dish network they have more hd channels and a far better picture they also have block buster at home where u can watch movies from ur dvr or have them sent to ya