Apache JMeter Review

Extremely light weight.

Very easy to download and setup the entire infrastructure (Controller +LGs)

Ease of scripting

Host of plugins which further boost its effectiveness

Availability Non-GUI mode which consumes even lesser resources than already lightweight GUI version.

Robust scripts which could handle build changes

Easy LG(Master & Slaves) configuration setup

Very lightweight and low usage of resources 

GUI tends to freeze and shutdown under more load

Ctrl+z( Undo doesn't work) so gets very inconvenient at times

Cannot do a mass replace( Ctrl+H) on the GUI ( can do it if script is opened via notepad++)

Re-iteration problems during errors - Usually we have login in once only controller, Action in Loop controller and logout in once only controller. Now if an error comes when the user simply logouts due to some unhandled error then the script expects that your session would continue but if that error has made you logout then your next iterations won't go through and vice versa. Suppose you put everything in loop controller and error doesn't log you out then the script start to login when you are already logged in and tends to fail.

We've had no issues with deployment.

See above Room for Improvement.

We've had no issues with scalability.