Ugh, guys, stop arguing about which one is better. There is a reason why Blizz put both of the systems in place, one is much more user-friendly, thus why GUI has certain limitations, while the other is more advance and more complex, but permits many new possibilities to the mapper.
I wouldn't say that a GUI user isn't serious about his maps. Heck I'm a GUI user and I am 100% committed to what I do and I can do 100% of what I want to do in my maps. To me, GUI is perfect for what I use in the SC2 editor. And plus, from what I heard, GUI doesn't have as many limitations in SC2 then it had in WC3.
I'm not defending anything or anybody, one little thing I'd like to point out: To those GUI users in SC2, it is much easier to do what you did before in WC3, because you already have that general knowledge of how things worked

. To those Jass, vJass, xyavfhsbJass or whatever Jass you used, you have to learn everything anew because the coding has changed to Galaxy

.
Honestly though, after playing around with the Editor for 3 months now, I am ready to learn Galaxy because it does look more efficient and it does seem to be a time-saver.