I was ambivalent towards it at first, but I've grown to dislike it intensely.
Underlying its introduction is a basic mistake: "overtaking is exciting". Actually, in turns out that one car driving past another car
isn't necessarily exciting - this statement disguises a greater complexity of value.
One of the things that's exciting about overtaking is the idea that you can ask different engineering teams to construct incredibly sophisticated racing machines, and when you ask them to race each other on a circuit, hey presto - they don't just follow each other around, they sometimes engage in these fascinating duels of wheel-to-wheel combat. I find this result aesthetically pleasing; DRS takes away that pleasure, by directly intervening in the events to ensure that passing takes place. Part of the beauty of racing is that it happens naturally, when you put men (or Danica) in cars and ask them to cross the finish line first. When I see the ridiculous invisible hand of DRS send a car flying past another with unnatural speed, I feel like I'm watching Scalextric cars: set them up on the straight, and race - nope, one of them's come off, stop racing - set up again, and race! Isn't this exciting!
It's also exciting when a following driver completely surprises the lead driver; for example
Hamilton on Raikkonen in Monza 2007,
Schumacher on Hill in Estoril 1995,
Montoya on Schumacher in Spa 2004. The DRS zone renders this kind of subtlety unnecessary, because there's little point in risking such a manoeuvre when the long straight inevitably provides by far the best passing opportunity.
Sometimes, the DRS zone also reduces the complexity of overtakes. Button's overtake on Alonso in the last race was set up by compromising Alonso into the S do Senna, holding the tow through turn 3 and then finally passing him into turn 4 - this kind of extended passing manoeuvre was facilitated by the fact that the DRS zone in Brazil was minimal. On the other hand when the zone is long and situated on the main straight, generally the complexity of most passes amounts to "get in the 1-second zone, point your car in the right direction and brake reasonably late as you pass him" - dull.
The effect of DRS on the aesthetic quality of racing is also profound in another way. You can see a slipstream developing over a number of seconds, gradually, as the following car picks up pace and prepares to pull out - DRS passes on the other hand often seem to come out of nowhere (but without the elegance of the aforementioned "surprise" overtakes), and are difficult to predict based on the general pace of the cars. The 1-second criterion for DRS activation is completely arbitrary, so instead of being simple and intuitive, following a multi-lap battle between cars often devolves into an exercise of paying attention to whether this criterion has been met (something that the viewer often can't even see for himself until the activation point is reached).
Excitement in racing (or in general) is something that develops gradually, increasing in intensity to a peak. The crowd at a football match or boxing contest always becomes most excited during a long exchange - a goal from nowhere, or a one-punch KO, are generally much less exciting than a goal that the crowd anticipates, or a
Corrales-Castillo style ebb-and-flow. DRS passes are disjointed; lacking the natural flow of slipstreaming-enabled passes, they are not a substitute for slipstreaming as some have claimed, and they also lack the compensating factor that a goal from nothing or one-punch KO is often the aesthetically pleasing product of extreme skill.
Finally, DRS tends to produce ordering of cars by inherent pace, defeating the distinction between racing and time-trialling. The fact that slower cars can sometimes hold back faster cars is the whole point of having cars race together on a circuit, so ease of passing is far from being a strictly good thing even when the following driver/car is clearly faster than the driver/car in front. How many races have there been this season in which a midfield driver successfully kept one of the big 6 behind him until the chequered flag, given that the driver of the faster car had been able to catch up to him?
On the other hand I will say that in general the quality of the racing has improved this year. But I think that much of that has been down to the tyres, particularly in the first half of the season when the teams were unused to the new regulations. The same phenomenon, of better racing in the first half of the season, was observed in 2010 - this has something to do with the distribution of good and poor circuits in the calendar, but it seems to me that a change of regulations in itself is something that promotes more exciting racing (perhaps because the teams' race strategies are less optimised). And as time has gone on, I've enjoyed DRS-enabled passes less and less - the novelty has worn off. I would scrap DRS.