What do you like best?
Turns spreadsheet and "table" structured data sources into multi-platform apps extremely quickly. Up and running in minutes, and can just tweak and adjust all you like. This is not only a tool to layout an app, but it includes a very strong set of automation as well as app management tools (versioning, security, user management, performance, and even use history monitoring and analytics).
The license model is great for rapid experiments, as all features are available for free if the app is not "deployed" and used by no more than 10 users - and always free for private use. This is an extremely good way to not only test the solution, but to actually create and use working apps for personal uses.
The other thing I really like about appsheet is the team. They are extremely active helping users on the G+ site, and roll out new features quickly. This is actually quite amazing as it is not just restricted to paying users.
What do you dislike?
Not much I "dislike" here. I was very impressed how fast I could "spin up" a very capable app.
There are some things that could mean this solution will not always be the best approach:
1. The platform is really targeted at data-sheet driven apps, and not that well suited to pure content driven apps that need great aesthetics and creative design flows.
2. To keep things very simple and leverage the easy connection to spreadsheets, the relationship between what is happening in the sheets and the appsheet tables/slices/views can take a little getting used to.
3. The help is not bad, but building the needed field formulas (expressions) takes some time learning as the syntax is a bit "irregular" and the expression builder (as good as it is) does not have syntax help or even formula definitions to help guide the app builder.
4. Some features have limited configuration capability so can be tricky to accomplish what you want (but it's "no-code"). An example is, they have decent chart views with drilldown, but you cannot configure the drilldown view (formats, columns showing, etc.)
What business problems are you solving with the product? What benefits have you realized?
The platform allowed me to experiment with mobile apps extremely quickly, to test user needs and adjust on-the-fly. In many cases we can take large spreadsheets that are only easily viewed on monitors, and turn then into mobile-enabled apps. Being able to view data on-the-fly is great, but even better was the gain in efficiency of being able to add/update/delete information on a mobile platform and automatically sync the changes to the shared sheets other users are accessing.