From personal practical experience, i'd say liquids drip more and absorbs a bit faster: That's about it. Simply put: Liquid is annoying to work with, but it seems to hit better for some reason. Although i have never tried this with DOC: But 25i-nBOME dissolved in alcohol was another magnitude above powder: 2mg on both times were completely different experiences. With liquid every aspect of ordinary reality was swept away in less than 5 minutes. With powder it felt like a mild dose of acid except much more stimulating and less mental. Strangely both were from the same stock and from properly measured doses too.
I've no idea how that relates to DOC: But i wouldn't be surprised if it was a similar case. Liquid simply seems to absorb somewhat faster.
The dripping is a problem with painful substances: No idea how painful DOC is, my guess is: Not very. But 25i-nBOME hurts like HELL. And 2C-E. I have that in liquid form: It's worse than the powder and you'll feel it all the way in your throat / stomach. Worst thing ever: I'll never put that shit in my nose in liquid form ever again. I wasted 5-10 mg immediately trying to get rid of it because of the intense burning.
/E: And yeah basically, just put it in your nose, and poof. It's very difficult to see the dose you're taking: So practice first.