Reboo is legit. I was skeptical about it working within my web-app since it's not on a builder per se, but it's working fine. Simple design tweaks are all I've done so far, but the feature set is quite large. I would like to see a progress bar or wizard option as someone else requested, but there may be a workaround with the other features.

On top of that, their support is superb and took action immediately with a minor bug repair. Five tacos strong, Reboo is a fun desktop app that will help with front-end design.