My best friend, who also has generalized anxiety disorder, PTSD, and depression, is on this medication. Thankfully, it works VERY well for him. I saw the improvement almost overnight after the first week or two of him being on it.
It's certainly worth a try. If it doesn't work, you can move on to other medications. I've never tried this one, but agree with the sentiment that I had to look for the right medications for over a decade in order to find a combination that worked.
Each new med usually needs a few weeks to months to really get a feel for how it will work for you, and to get past the window of the biggest side effects.
If the side effects subside and the benefits outweigh them, then the psychiatrist will up your dose as necessary over the next few months or years to get to the best balance of med benefits with minimal side effects.
Here's to hoping you're as lucky as my friend and it works for you

(it's apple juice -- pretty sure you need to avoid alcohol while on it!) -- my friend has had to up the dose several times in the last two years, but the results are very helpful for preventing that paralyzing anxiety and symptoms of depression