I have DirecTV, my parents have Dish. Both are pretty much equivalent as far as picture quality, channel selection, and price. If it matters, DirecTV gives you music channels from XM satellite radio; Dish gives you music channels from Sirius satellite radio.
I self installed my own dish because I live in an apartment and the installer gave me the third degree about bolting a dish to the side of the building and wanted to charge me extra to do the 'pole in a bucket of concrete' thing, so I told him to bite me and made my own pole in a bucket. Later I extended the pole to accomodate tree growth by u-clamping the pole to my balcony railing and bolting the base to the deck.
Picture quality on both is excellent. Even with my new HDTV which doesn't get any HD signals it's crisp on ALL channels. My parents' 32" SDTV looks beautiful with their Dish.
Rain fade happens, but it requires one of those big honking thunderstorms that tends to destroy things on the ground. Also it is a thunderstorm that is a few miles away to the south that will interfere with the signal, and since they usually move pretty quickly/dissapate outages are not more than 5-15 minutes at any given time for either provider. Cable I've had out for days due to extreme weather. As soon as the weather goes away (and you get power back, assuming that happened too) you get your signal back. Normal "It's gonna rain all day" type rain doesn't do anything to the signal. If it does, your installer screwed the pooch and didn't align your dish properly (either provider.) Snow really doesn't do anything to the signal unless it's that wet clingy type with heavy accumulation. I've only had to brush snow off my dish once in the three years I've had it.
Not sure how it is with Dish, but with Direct if you get the urge to get a package or premium channel such as HBO or the sport package, it's a quick trip to the website, enter your account info (and password) flip a few switches and BAM you have your new channels. Used to be you could switch it off the next day and just be billed for the one day, but now you have to keep it for at least 30 days before you turn it off. But turn it off immediately via the internet you can.
All in all, I've been happy with my satellite service, and my parents have been happy with theirs. Actually, that's an understatement. Both my parents and I are pretty much 'cable? what?' as far as that's concerned.