If the "no-code" choice hides the complexity of data integration, it also limits the tool's flexibility as well. Indeed, by choosing the "zero code" solution, it becomes also difficult to deal with the need for customized processing. That's why Apatar is more geared toward data mashups than toward Extracting Transforming and Loading data (so to speak ETL).

If you want a tool that's well-balanced between capabilities and user-friendliness you might want to have a look at Talend Open Studio. It is a powerful (and open source) ETL software but remains user-friendly through its GUI that is very intuitive.