I've had SlingTV for over a year now, so I can give you a pretty good pro/con list.
Pros:
Cheap - $20/month for basic package that comes with around 40 channels. Basically every channel I ever bother watching on satellite. Add the sports package for $5 more and you get all ESPN's as well as like 10 other sports channels I never watch.
Watch Anywhere - It's an app, so I can watch TV at home on my TV, IPAD, or smartphone. That's awesome so I can watch TV from anywhere, even work. Keep that last part quiet.
Easy to Setup - No installation guys coming that you have to wait on all day because they gave you an eight hour window. You just download the app, sign up, and start watching.
Good Customer Service - I've called them several times, and they've always solved my problem quickly. Never had to wait forever for someone to pick up the phone either.
Cons:
Need Good Internet - For it to work properly without any buffering I had to upgrade my internet to the highest speed available. I didn't mind because it makes everything else in my house that uses internet faster too, but if you just have basic speed you might not get good streaming with this.
No DVR - If you're one of those people who likes to record shows and watch them later, they currently don't have this feature. I've never had a DVR, so I'm not missing anything but it turns some people off to this.
Lags behind Satellite - When watching games, the stream comes in about a minute or two slower than satellite. So everyone will know the outcome of the game before you do. Like I can get on my ESPN app and see that UK has scored about 30 in game seconds before we actually do. (I totally cheat on close games so I know if we lose or not. Never told my wife though. lol)
Can't watch different shows at same time - So you can download the app on multiple TV's but you and your wife for instance can't watch different shows at the same time. The only way to do this would be to have multiple SlingTV accounts, which would cost you another $20. It's not an issue for me, but it could be for people who don't watch TV together.
All in all I love Sling. Saved me $100/month, and I get everything I want from TV anyways. They usually offer a free week trial. You should give it a shot and see if you like it.