Sprout
Bluelight Crew
There's a distinction to be made between shorter and longer half-life SSRIs, I will put forth personal experience CTing from fluoxetine (on about a week now) as not being particularly bad, however citalopram has a much shorter half-life, and therefore will have far greater risk of worse withdrawals, and I am fully prepared to accept Sprout's claims on the matter. Short half-life SSRIs like citalopram or sertraline absolutely need to be tapered or switched to a long half-life SSRI like fluoxetine before stopping.
It's very difficult to assign a quantitative scale given the very nature of their indication and the specific neural plasticity of the recipient.
Those with "mild/moderate" (the most awful terminology, I know, but one must differentiate severity) unipolar depression tend to experience less intense symptoms than those who inhabited a state of suicidal desperation prior - even before the neurochemical impact there is the issue of relativity.