For me it helps when I have that anxious tension in the pit of my stomach anxiety. I usually have it at night. I'll take 0.5mgs of clonazepam before bed and I'm able to sleep better and I feel really calm the next day.
My psychiatrist prescribed it for me because it lasts longer than other forms of benzos, particularly ativan, and I find it doesn't dope me up like ativan does (and I'm not as sleepy and I don't have any hard crashes like I do with ativan the next day).
If it wasn't a benzo and addictive (only takes is when you absolutely have to!), I'd say screw it to SSRIs and just stick with the clonazepam!