I work with all of them as a Microsoft Certified Trainer, particularly around the Business Intelligence SQL space. I tend to do quite a bit of work around the SSAS space, SSIS, SSRS, and integrating that into a lot of SharePoint and other spaces.
The challenge is building from the KPIs. Being able to put your KPIs in place starting with understanding a board of directors and their needs, and being able to build the KPIs for an organization from that level is important. Then being able to deliver those on a dashboard, such as Power BI, or something else, also matters. Additionally, being able to build cubes that allow for rapid analysis over a long period of time is crucial. The one thing which is missing often enough is building out your data warehouse with your data models, so helping to build the data models is very important. I appreciate how it handles large data in your warehouse.
Stability is rated at 10. One other important aspect I appreciate is that SSAS is included in the base installation of SQL Server. Obviously, it requires installation, but it is readily available, which is a major strength. It's all about setting it up, configuring it, and then using it. If there are additional costs associated with it or separating it as a second product, that would be a disadvantage.
The area of improvement is really in education. Microsoft is trying to push everything as a Power BI solution or trying to get people to solve the problems which are solved with SSAS in another space in Power BI, or in Power Pivot, is not enough. There's not enough marketing, conversation, and support around that space. As a result, we end up with people not understanding that you need to build your models correctly, and then they try to model everything inside of Power BI, or another visualization tool, without first building the data model.
That leads people to consider alternate solutions because SAP and others argue that their whole thing is in memory, and they disseminate misleading information. Additionally, what would be very helpful is local user group developments, so getting people around the table and teaching them how to use it. That is the biggest problem; it's not the technology itself. The challenge lies in Microsoft withdrawing a lot of the qualifications and watering down its emphasis, leading to a perception that this is supposed to be an elite product.