How does venlafaxine differ from other antidepressants

Venlafaxine seems to have the relative freedom from side-effects associated with the SSRIs [fluoxetine (Prozac), sertraline (Zoloft), paroxetine (Paxil), and fluvoxamine (Luvox)] and the impact on both serotonin and norepinephrine associated with the tricyclic antidepressants [amitriptyline (Elavil), imipramine (Tofranil), etc.]. It is hypothesized that the action of the venlafaxine molecule upon both serotonin and norepinephrine will cause venlafaxine to be a successful antidepressant for some people who have not responded to treatment with SSRIs.