The classic ASP.NET is stand alone and inProc in nature so it has some limitations. It is good for smaller web farms only but when your app is running in a multi-server environment, it may ends up with some performance and scalability issues. So the use of a third party distributed is recommended as the cache in this case is distributed over multiple servers so it not only boost the performance of the app but also provides the scalable data all the time. Even MicroSoft itself realized this factor and they have introduced MS AppFabric. But when it comes to distributed aching, NCache is a matures and well established distributed cache provider.
NCache is an in-memory object caching solution for .NET applications with real-time data access needs. It not only lets you cache read-only data but also complex transactional data with relationships. As a result, your application can cache most of its data and improve performance. NCache helps remove performance& scalability bottlenecks related to your data storage and databases and scale your .NET and Java apps to extreme transaction processing (XTP)
Alachisoft, the makers of NCache and StorageEdge for SharePoint has recently released the latest version of NCache i.e. NCache 4.1. In this release, the following features have been added along with the features of earlier edition, NCache 3.8 SP4,
1. String sharing between Java and .NET (vice versa)
2. SQL Cache Dependency Custom Queue/Notification Service
There are three different editions of NCache are available which are,
You can learn more about the different features of these editions from the edition comparison list.