I had cablevision and recently switched to dish. Cablevision rates went up over $50 a month after promo. Dish is much better than Cablevision.
My parents use Time Warner, and have the DVR. I think that it works great. It is very comparable to Dish from what I have seen. I get the feeling that so many people love the dish dvr for features that the average person could care less about. I'm not complaining, it works great, but I don't see what all the fuss is about. I had PIP with cable and never used it. You will get your locals with TWC, so you won't need the ota tuner that dish has. You will be able to record two things at once, with TWC. (In my opinion, if you have to record 3 things at a time, like the dish DVR allows, with an OTA, then you need to get out a little more anyway.)
Also, my parents promo just ran out for the truple play, and the bill only went up about $10 per month. The good thing is that you can try out TWC, and if you don't like it, I beleive that you don't have to sign any contracts. (just check before you do sign) If you like it, use it for the promo period, and if the bill goes up, then switch.