Adoption of SAP PI platform is growing rapidly, primarily for SAP’s application customer base. However, despite SAP’s crucial improvements, PI is still lacking of most-advanced platforms’ abilities. But it will still be used commonly by SAP base customers.
Graph below, shows the roadmap of SAP PI starting from SAP XI versions. From my point of view, there are 3 major versions of product. Phase 1 is SAP XI 2.0 and SAP XI 3.0, phase 2 is SAP PI 7.0 and phase 3 is SAP PI 7.1. SAP invested a lot of engineering hours for PI and tried to provide the most up to date features in it. But, like all the products in integration platforms market, PI has some pros and cons.
Graph 1: SAP PI product versions
In particular, SAP PI is proven as SAP oriented product and is widely used by SAP customers. According to a statistic from SAP, only 5% of the PI or XI users are non-SAP customers. So, it clearly shows that PI is very SAP centric product and fits better to SAP product portfolio.
On the other hand, well known vendors like IBM, Microsoft, Tibco, Sun Microsystems are functionally richer than SAP PI because they focus not only to SAP but also to other application packages. For example they provide much complex event processing, business activity monitoring and other advanced integration features. However, PI is highly optimized for SAP systems and provide much more pre-built integration metadata and it is more similar to SAP systems.
SAP PI license for SAP-to-SAP usage is included in NetWeaver 2004 suite license and MySAP license. For SAP to Non-SAP integration PI base engine is priced based on the overall processed message volume expressed in Gigabytes (GB) per month. For some large SAP customers, special discounts are available and price mentality of SAP is “more you use less you pay” (we can also call it progressive scale).
To match PI with Microsoft BizTalk technology, please refer to the graph 2 below.
Graph 2: SAP PI and BizTalk Functional Coverage
You can download the full version of research paper from here: High Level Comparison of SAP PI and MS BizTalk
IT - Telecom Business 
