I've been leveling weaver and botanist together, trying to keep them about the same. My impression is that botany has been far more grindy than weaving.
Doing a level 25 crafting leve and hqing it resulted in somewhere between 40% - 50% of a level at levels 28 and 29. This was a single item craft that required fairly little resources to craft. It was also fairly easy to HQ because it required two items that were for the previous tier of items. Granted, this leve was picked up in Ul'Dah and delivered in Quarrymill, but travel was fairly trivial once Quarrymill was favored.
My other impression is that I could comfortably level just grind crafting and using leves as nice bursts of exp.
However, with botany, levels 25-31 would have felt nearly impossible without leves. Granted, since hitting 31, I've noticed that grind gathering is making for a somewhat better pace than it ever was during the 25-31 level range.