In the newest release of Hack, I'll use it on embark to prospect, as it reveals the layer stones. For those unaware, you used to get a list of layer stones on the embark screen, like dolomite or granite or whatever. I enjoyed this, and I think that the short men borne of the mountains would know how to prospect what layer stones are there...
Reveal, rarely. Mostly to find where the layer stones are so I can work on my marble fortress. But now prospector will show where the layers are, so I've got no need.
Autodump - never. Hauling is a part of fortress life and a viable life skill for fresh migrants. If it's not needed then I rig it to be stockpiled into areas that are then doused in magma. Rarely "claim owned" or whatever that one is, mostly just to get that one claimed troll fur thong off the one wall tile so I can defend myself, y'know?
It's the newest tools that fascinate me the most. Workflow in particular is an amazing tool. I use it for specific tasks, like keeping booze in stock - something that dwarves should do without supervision, I imagine. I'll also use it for construction purposes, like keeping X number of marble blocks in stock, so that construction may continue smoothly without having to creatively forbid and fiddle with stockpiles. I already have a full-time manager, so I can reasonably hand-wave that, imagining that the manager is just checking on the work orders.
Liquids rarely. Sometimes if things get stuck, like a tile is registered as "warm" when there's no magma, I'll place 1/7 magma and let it evaporate to fix that little issue.
Cleaning, depends. I don't meddle with FB these days, I'm focusing on surface exploitation, so I'm not making things easier by removing syndromes. I'll speed up my FPS a bit by cleaning things, but that's only because dwarves don't do it themselves. If I could designate a zone to be cleaned, I wouldn't need hack for that.
So for me? I use hack to make specific workshop orders easier - something that should be in vanilla. Toady has acknowledged that we need to be able to specify what kind of stone for the mason workshop to use, so this is just the third-party tool that makes it possible early. I don't use it to make things easier or to reduce the labor load. Dwarves need to have jobs, and hauling is a valuable skill. Let them scour the field retrieving goblin junk!
Although on that note, I often mod goblins to wear less clothing, so my issues are less in that regard. Less socks and thongs to clean up, though they generally wear more armor than vanilla so I imagine it balances.