Depends on needs and familiarity. I used Bash and Curl, then PHP, then settled on Jmeter for a tricky bug due to a memory leak from a race under load. All three

Depends on needs and familiarity. I used Bash and Curl, then PHP, then settled on Jmeter for a tricky bug due to a memory leak from a race under load. All three could reproduce the problem. Jmeter had quite a learning curve, and preparing data for it was a pain. Ultimately though it was more reliable, can do distributed testing, and has lots of nice built in features and analytics.