On the other side of the web, I kept discussing Harmony with Allison (Canonical) until I asked something and got no response anymore.
Bringing up arguments like "it provides more clarity to contributors, a 'check point' to look at the legal situation and reassurance of legal status to users" or the already-debunked "but it is helps protect the copyrights and handling of disappearing contributors" doesn't convince me that contributors should sign away their code while running the risk TO GET SUED BY THE COMPANY THEY JUST GAVE THEIR CODE TO FOR WRITING IT IN THE FIRST PLACE. Seriously, that's a risk, read Michael's post.
The whole problem with CLA's and the like is and remains that you give but don't get even the least of protection or right. All risk remains with you - if you overlooked any patents on the code you just signed away to the company, they can sue you, or let others do so. And you can infringe on patents of the code you yourself just wrote. And in case you're defending yourself in court, they can sell your patents you need to defend yourself to the company attacking you (or they already might have, years ago). So they get to monetize your contribution any way they see fit, including selling it to the highest bidder, patenting it and suing anyone who writes something similar. You get - well, what do you mean, you want something?
You got to write code for them, didn't you? For free! You should be happy you got to contribute to such a great company! Now get out of the way or we sue you!
Honestly, I wasn't enthusiastic about Harmony but as I'm no lawyer and not really capable of reading the legal speak of the (hard to get to) licenses I didn't know it was that bad. Ok, it's a 1.0 release, signing it might burn your house or let anyone sue you. I'd say a warning on the site might be in place...
Read Michael Meeks' interesting insights. Little to say after that, imho. The pro arguments are not convincing at all, the con's are big. I'd recommend to never sign a CLA or work for any company requiring you to do so - unless they pay you of course. After all, that's the whole point:
If a company wants ownership to your code, they should pay you!