NeoLoad works at protocol level so it uses its own HTTP client. That's why you do not see any differences.

If you do see high response time in IE then the issue is more a rendering issue on the client side and not a server issue. You may have some Javascripts for which the execution is slower in IE compared to Chrome. 

You do not have a browser emulation in NeoLoad. It's only the User-agent that will be modified.

It is useful when for example you would like to reach a mobile application. By changing the user-agent you will be redirected to the mobile web site.

On the browser-simulation:

• user-agent can be customized
• number of parallel connections
• whether or nor SPDY is supported
• How cookies are handled (minor changes for some browsers)

You should look at the First Time To First Byte (TTFB) statistics, it represents basically the server time + the network latency to receive the first bytes of the response.

Average Time - TTFB = Download time, useful to check the network.

Protocol level means that NeoLoad records and replays the HTTP requests. All the client part like Javascripts are not executed.