1) It needs to be installed on every client workstation
2) Data visualizations available are more suited for operational reporting than analytical reporting
3) There are almost no features for collaboration i.e. sharing generated reports with other users on a common platform unless you use Office Web Apps or Sharepoint
4) No spatial data support either in consumption or presentation with Bing Maps / Google Maps
Actually Excel has the capability to use OLAP / SSAS cube as a data source, but that does not mean that this capability can be treated as the primary purpose of using Excel. In one of my posts, I mentioned about Analyzer which is a product from Strategy Companion. Recently I came across one another such product - Report Portal.
Zero footprint, SaaS, Cloud are some of the buzz words while selecting a technology / product for solution development, and Report Portal is also a zero footprint OLAP web client for SSAS. In my view, this product lacks that professional and sleek features that is expected from a web client. Documentation is quite poor, export formats of reports are limited, there is no mention of SaaS offering. But some of the noteworthy features of this product are as below:
1) Report portal has got very distinguished data visualizations, which are quite impressive from a data browsing point of view. You would not use these kind of data visualizations generally for reporting, but to develop analytical reports, these visualizations can be quite helpful for analysis. Check out the Pie-Chart Tree Report, which is one of the quite unique kind of data visualization for data analysis.
3) Metadata can be browsed very efficiently, and this product makes a very extensive use of XML/A ( XML for Analysis ). The browsing features are quite friendly to take away the pain of forming MDX queries.
If you use it as a tool to save your OLAP analysis i.e. the results that you gathered while browsing or analyzing OLAP data, and want to stick it in the form of reports on a collaborative platform, it's a nice web client with zero footprint installation ( as it's a web based solution ). But if you are looking out to use as a full fledged self-service enterprise reporting solution out of your OLAP, I would feel much more comfortable and confident in Analyzer than Report Portal.
A wise strategic move can be to use Report Portal when you are taking your baby steps in your OLAP reporting i.e. the phase when you are developing your data marts / data warehouse. This product could well support your OLAP browsing needs efficiently as well as facilitate reporting at the same time, keeping the pressure of immediate reporting from your evolving data warehouse, at bay. When the solution is in the next level, you can choose a SaaS reporting solution like Analyzer and retire Report Portal. Please keep in view, this always depends upon scenarios and it's not a generalized strategy. The key difference between Analyzer and Report Portal is that Analyzer is a reporting solution, and Report portal is a web client and reporting is one of it's features and not a primary function.