Moqups vs FluidUI

Moqups is built in HTML5 and standard Javascript, so it doesn't require any plugins to use. The application is very fast to use.

As well as a standard snap-to-grid, Moqups supports the 960 gridsystem.

The Free Plan offers 2 active projects with at most 300 stencils each and 5 MB of storage. This plan does not include: Master Pages, Real Time Collaboration, Privacy Settings, Unlimited Revisions, Unlimited Project Archiving and Teams.

Moqups has an extensive list of keyboard shortcuts. Simply type some A-Z letters to search for components. F1 for an overlay help screen.

The learning curve is relatively low compared to other software that supports animations/transitions. Both building the wireframes and designing the interactions is all drop and drag.

Work with your team on a design. Connect on live video calls and chat or add comments.

You can simulate all the typical iOS gestures such as tap, double tap, swipe & long hold. These gestures then can trigger animated transitions such as sliding, fading, pop in, & flip. This enables you to create very realistic interactable demos of your app. Checkout the demo page for some examples.

Every action you or your team takes automatically creates a revision you can easily revert to.

The UI library is huge and very high quality. All the UI required to design iO7 apps is included as well as iOS 6 and basic wireframing elements. For example in iOS7 it provides:

• Backgrounds
• Navigation & status bars
• Layouts (list pickers, maps, keyboards, scroll etc)
• Controls
• Typography
• Icons

Using the app is feels very snappy.

They have a very reasonable free tier with the paid versions starting at $12/month.

You can preview your designs live in the browser as well as send them to a mobile device to better simulate the UX.

Fluid isn't just about wireframing static screens. You can plan out all the user flows and then define the transitions between them. This is really handy for planning out the entire user workflow.