Hacknot has published an excellent article on GUI Builders: Beware The GUI Builder
Considering the hype around Netbeans “Matisse” and Eclipse VE in the java desktop community these days, this has appeared at the right time.

GUI Builders are useful, to an extent, but for real application development they are a pain to use.
The biggest gripe I have is round trips. You build a UI using the builder and it generated a piece of code for you. Now you want to customize some parts, change names or any such thing. You can’t just open the java code and modify. Depending on the builder you use, it may support absolutely no round trips or some round trip support (usually not very good).
The second thing I dislike is component names. Most builder user sequential names like label1, label2… . Yes they allow the user to modify the name, but usually after 2-3 mouse clicks. Same goes for event wiring and internationalization.
And then there’s maintenance. I have had the misfortune of inheriting UIs that have been developed with builder and believe me its a pain.

So if you are interviewing someone who claims to be a UI person and their preferred way of building UIs is GUI Builder, you may want to dig a little deeper to ascertain the facts.