Are the symptoms of viral hemorrhagic fevers bad?

Yes: Specific symptoms vary by the type of vhf, but symptoms often include fever, fatigue, muscle aches, and exhaustion. Patients with severe cases of vhf often show signs of bleeding under the skin, in internal organs, or from body orifices like the mouth, eyes, or ears. Severe cases also cause any organ to fail, with shock, coma, and death.

Usually quite bad.: Reston Ebola virus is non-pathogenic in humans. These VHF's are bad: Marburg hemorrhagic fever, Crimean-Congo hemorrhagic fever, Lassa fever, Ebola, Argentine hemorrhagic fever, Yellow Fever, Rift Valley Fever, Hantaan hemorrhagic fever,Omsk hemorrhagic fever, Kyasanur forest disease & Dengue Fever.