The main thing I like about spritebuilder it's ability to generate code for all major languages ( Objective C, Java ). It has many useful tools including level editor which makes building levels much easier than any other IDE when you don't know how things are done with Xcode or Flash Builder etc.. There could be some minor bugs here n there but they're mostly small issues compared what we can have from using flash builder so far everything seems perfect :). Sometimes generating classes/headers might not work as expected if your target language doesn’t support something needed by certain features e g reflection API sometimes fails even though class generated works fine -_-.