The "cry it out" method (or CIO as it's annoying referred to on the baby forums -- acronyms central) does not actually advocate leaving the child for long stretches of time. It is a common misconception based on people not actually reading about the method, or the person who originally advocated it (Ferber).
For us, we had to do it at around 4 months or we would have been in serious trouble. 4 months of averaging 2-3 hours of uninterrupted sleep per week was wreaking havoc on our lives, and no one (including baby) was happy. The only way she would ever sleep is in our bed next to mum, and this was not sustainable, and terrified us every single night.
We read all of the no-cry sleep methods, and ferber. We realized that we were essentially doing all of the no-cry methods already (swaddle, side sleep, white noise, pick-up and soothe immediately, co-sleep, cradle at the side of the bed) and we tried each one for weeks.
None of it worked. At all.
For the Ferber method, you only leave the child for a few minutes at a time and gradually increase it. In our case, she was never left alone for longer than 10 minutes (we couldn't do any longer) and we did it over weeks and as gradually as we could. Now she sleeps in 4+ hours segments regularly which, to us, has been a god send.
To each their own. No one method is foolproof as all babies are different and I've learned through this that I no longer trust "experts" or anecdotal evidence. I will use it as a guideline, but adjust based on my own observations. I don't think any other approach works.