Also not quite the same as rotten! And, I would hazard a guess that the consumption ratio of inlagd-sill to surströmming is at least 1000:1, maybe 100000:1.
Oh, tried to find it on the page but must have hidden the comment. I've never worked in it, but played around with it for a few minutes and it certainly seems capable enough for solo or small team use. It's also the only open source prototyping tool I've found yet.