Going back to Studio 3, I just read this on the CNET download page for Studio 3:

'This free version of DAZ Studio also doubles as the 30-day trial. Features for DAZ Studio 3 Advanced are enabled in the free version for 30 days, at which time they will be disabled unless the Advanced version is purchased. The Core version of DAZ Studio 3 will remain free.'

So after 30 days, unless you purchase Advanced, you won't have the GI and area lights anymore. So I guess it's a case of enjoy them, but maybe don't get used to them?

I may download it to try it out, but I'm so used to the Poser interface, I just couldn't make head nor tail of the older versions. I imagine it'll be the same with 3 as well! :)