Hi,
The main trade-off between transport layer protocols (such as Web HTTP) and UI-based protocols (such as TruClient IE) is scalability vs. usability.
With Web HTTP it usually takes a lot of effort to create and tune a script - you need to identify correlations, apply DFE's, recreate some of the client-side logic within the script etc. In return you're getting an extraordinary scalability, up to thousands of vusers per LG machine.
With TruClient creating a script is very simple, usually you just need to perform your business process during the recording, and that's it. The post-processing is minimal. However, the scalability is much lower than that of Web HTTP, because actual browser instances are launched during the load test, consuming machine's resources. So, at best, you'll be able to run 50 vusers per machine.
