Less moving parts. If I get a request from a PM, I quickly open up Tableau, select a datasource or write some SQL and deploy. Sometimes data asks that they think would take 24 hours or more can be turned around in under an hour with Tableau. You can also train and hire less technical people to use Tableau...its basically like advanced Microsoft Word.
It depends on whether you want your BI to be generated by a battle tested product, or by a melange of a rickety, buggy, half baked stuff that hardly anyone is able to use without paying $10K+/yr for a support contract.
We jettisoned Pentaho about 2 years ago because of the effort required to develop and maintain it.
At the time, between the ETL and reporting layers, it acted more like a set of different open source apps simply branded together, and interop required more effort than what should have been necessary.
Debugging was a nightmare as well. Huge stack traces on simple errors made locating problems difficult, and there seemed to be little information in the community. The number of Java library layers spewing out on a simple JDBC driver error was mind-boggling. Pentaho of course has a interest in revenue from support contracts, and most inquiries into simple issues in the forums led down that path. It may have gotten better since, but there was a long way to go.
We switched to Tableau on the front end, and "old fashioned" ETL scripting in Python (now some Go) on the backend. At the same point today I would consider something like R/Shiny, but for speed of implementation Tableau would also be a contender.
Basically same here, but a few years earlier. I consider a three hundred line stack trace to be a valid reason to replace a system with something less operationally challenging. When engineers are $100+/hr, and some way more than that, it often ends up being cheaper as well.
No, although it required a little ingenuity. We would have considered using Shiny Server Pro for the auth and other features but we wanted to use our single sign on service. What we did was we put Nginx in front and had it call a tiny Rails app that handles authentication via the SSO. If Rails returns the correct status to Nginx, then the client is redirected to the Shiny page they requested.
Its a bit of a one-off but it does work well! One more step towards making R fit for production :)