I think for most people price is a pretty important consideration so it's hard to answer without knowing the rates for each, but if for some reason the prices are equal or similar: Standard View Club Level.
DTD rooms are further from the elevators and the view can be really hit or miss depending on where you're placed; you could find yourself looking at the top of a building with vents and pipes in sight. They can be fun if you luck out with a 6th floor view during the holidays — we've been there in December and could watch the "snowfall" in the evenings — but most of the time they're not worth the walk or the price, IMO.
With Standard View Club Level, you're guaranteed a higher floor (5th or 6th), since the room assigners will try to minimize your walk to the lounge. You also have a wider range of possible locations so room requests can potentially place you closer to great locations in the building (close to the lobby elevators or DCA entrance elevators). And, of course, you get to stay Club Level, which again, if the price is the same, is a way bigger benefit than looking into DTD.
GCH is one of those resorts where the public spaces and park proximity are what make it special — the views from the rooms are all more or less good enough. (Our go-to is usually the Woods-Courtyard view, which is peaceful and immersive and just one level up from Standard.) If you want a view of DTD, I'd actually recommend the Premium Downtown Disney View rooms or Club Level Premium View rooms at the
Disneyland Hotel — they're not as close, but you can see down all of DTD and both parks.