I should also point out that there is a clause in the commercial license for Qt that means that you cannot start development (or cross) with the LGPL or GPL versions, once you use a non commercial license you cannot use a less restrictive license, regardless of whether you have such a license.

I don't know how this would play out in court, but the idea was that by having a clause like this prevents organisations paying for a single commercial seat (for final build) and then allowing all their developers to use free editions for development.