That was the killer for me. I was quite excited about SproutCore, specially after reading in one of the docs (which, apparently, are severely outdated) that "you could bring it down to something around 300kb uncompressed". Heck, even iPhone users can load 100kb compressed data. But then the generated application was always megabytes big, even when compressed. It's still manageable if you have a heavy application, but kind of overkill for what I need.