thanks for your inquiry! I quote our license on this:
"soapUI Professional Personal Edition is for personal use only. You shall not use the software in a commercial capacity or enterprise. You shall not use the software as a tool for commercial services."
so basically you can get it for "personal" use only.
We are working on decreasing both start-up times and memory consumption by adding the possibility to lazily load projects and have the possibility to "close" them without removing them from the workspace (like in eclipse for example) which would free up their associated memory (which can be quite alot if there are many messages,attachments,etc..).