InVision is a collaborative design and prototyping platform with features such as freehand drafting mode and interactive mockups, collaboration, idea management, user testing, and integration with Slack and other collaboration tools. According to the vendor, 1 million designers are using the free version.
We started using Marvel for rapid prototyping and the two are fairly analogous. In the end team and enterprise functionality drove the switch from one tool to the other. Another tool we had used is Axure, and for truly advanced, data driven prototyping, it's still the tool to …
OmniGraffle is a solid Mac based Visio with much added functionality specific to wireframe designs. The libraries, although somewhat out of date, allow rapid designs with low fidelity, exactly what you want in wire frames. We use Sketch increasingly to handle the layout of the …
Axure RP is almost unnecessarily complicated in some areas and the UI can be drastically improved. FlairBuilder is great overall but lack of or slow support is what hurts it. OmniGraffle is one of my top 2 choices currently and InvisionApp is the other.
Omnigraffle handles flows and diagrams better than other tools I've listed above. However, Axure is far superior for creating wireframes and turning them into interactive prototypes (basically "coding" using if/then logic statements). Sketch is much better for detailed design …
In comparison to Sketch, OmniGraffle is much better with connectors and placeholders. The placeholders were key for me as I use them often while building wireframes. It's so easy to access and drop in. I'm still trying to figure out how to download and sync stencils for Sketch …