Cloud of wasps, which is terrain dependant. Insects is not.

Also the likelihood of surviving a gank long enough to lose insects is minimal. At best you managed to escape despite still being under the insects affect and just don't have to deal with them for as long afterwards.

I don't have a dog in this fight as I'm in neither cabal and I've never had either power.

However, sigil does not scare me, because my opponent is lagging himself when he uses it and if the extra damage is expected to be a problem, I'll just run away before it is fatal. If I'm slept and sigil is placed on me I'll escape.

Insects does scare me. Running away from an outtie in the wilds is tough, particularly from the refuge. It's also hard to evade a Druid for long no matter where you are. On top of that, you can have it called on you while you are slept without being woken. Maybe even when snared without being freed. I forget but I do remember a close call where insects were placed on me without giving me a chance to flee.

Not to mention that insects prevents rest and does steady and significant damage.

Overall, it's the fact that you can't just run when it is applied that makes insects by far the nastier. Particularly as if may be applied without you having a clue that there's an attack incoming.