I am happier now, because it is giving us the opportunity to try restaurants that we wouldn't ordinarily. We just couldn't justify spending the $90+ that it would cost us to eat table service each night, we always ate off-site at night prior to the
DDP. So I can't comment on whether the service has declined or not, I have nothing to compare it to.
The way I look at it, the dining plan is what, $38 per person plus tax? So, let's assume $80 per day for the two of us to eat. What we used to do was spend about $10 on breakfast at the resort, $20 or so on lunch in a park, $10 or so on snacks inside the park, and then we would eat off-site at night, which averages about $40 or so.
So...basically, for the same amount of money, I buy the convenience of eating inside the parks/at the resort without the added travel time or having to decide where we were going.
Now, I have an ADR, it's pre-paid, and I eat. It kind of makes things simpler, and that's the value for me. The food is not exactly 5 star gourmet cuisine, but I don't expect it to be at a theme park. It's filling, and I've never had a BAD meal anywhere in WDW...in fact, most of it is quite good.
The lunch crowds at CS restaurants do bite, though. We try to eat really really early!