Sumit,
good question! My point on this: we actually took a different approach on logging with SmartInspect compared to log4j (and other similar logging tools). Instead of just providing support for logging simple text messages (yes, I know that you can also 'render' objects with log4j, but it's still mainly unstructured text), SmartInspect allows you to log more complex data structures such as lists, objects, images, source code, files and so on, allowing for richer log files and more useful and structured information (which helps you make more sense of the application behavior when analyzing the logging data).
Now, when you compare just the logging libraries, the additional information contained in the log files isn't helping a lot. But the main strength of SmartInspect is the Console application, the log viewer and live monitoring application that comes with SmartInspect:
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Analyzing large log files or monitoring applications in real-time can be very time-consuming, especially if the application is non-trivial (or if you generate quite a bit of logging data). The Console allows you to easily filter, highlight, view and analyze application logs, making it a lot easier to spot problems or to trace application behavior. SmartInspect also comes with unique features that have been designed especially for production usage that aren't found in other logging libraries (such as the Backlog feature or the SmartInspect Router log server application).
Of course, SmartInspect also comes with other things that improve the overall experience that are often missing in open source libraries, such as additional tools to visually build configuration files or the included commercial support.
I think it comes down to this: if you just want to create simple text log files, be it for end-users, admins or for developers, log4j is definitely a great library for this. If you want to save time analyzing log files, debug non-trivial systems, monitor applications in real time, create rich logging data or if you could benefit from additional features designed for production usage, I would suggest giving SmartInspect a try.
I'm really interested in your feedback on this.
Regards,
Dennis
