Best Business Intelligence tool in the market?

This is very tricky question, most folks in the business side think of BI as visualization tool because that is what they get to see but delivering BI solution is much more than building dashboards and reports. Modern BI solution consists of many components such as Database Engine, Big Data Processing Engine, ETL, Data Streaming Service, BI Semantic/Caching Layer, Visualization, Alerting etc.

Choosing right BI Solution involves many factors such as feature requirements, Size of the company, Size and Type of data, Employee Skill level, Budget and sometimes what other Products company is already using.

So better question to ask will be asking multiple questions such as below

1. Which is Best Visualization tool?

Tableau has most advanced visualizations along with much better alerting then Power BI but Power BI has Paginated Reports, Custom Visualizations and Natural Query language which Tableau currently does not have, Chose the tool based on features important to you.

2. Which is best Caching / Business Semantic Model Layer ?

Azure Analysis Services is the leader in this space with most enterprise features.

3. Which is best database engine for data warehousing?

Azure SQL DW seems to be best in the league as it has distribution, partitioning, high concurrency as well as external tables for Hadoop Distributed File System connectivity for large unstructured data.

4. Best Big Data Processing Platform?

Azure Data Lake analytics is only platform which lets you pay per each job submission and you can specify how many nodes you want to use to process the job, this will be most economical option for mid size organizations who do not have 24 by 7 big data workloads.

5. Best Streaming Data Processing Platform?

Azure stream analytics pay per job can help you get started quickly and one can later move to other platform if your organization have enough streaming workload.

6. Best ETL tool?

Both Azure Data factory and Amazon Data Pipeline has pay per job model and can also orchestrate/scale data processing compute servers on demand, choice should depend on what other software are part of your data ecosystem.