Depends really on what you have on hand and what is your occupation. The Vamp Blade and the Shock Gun will not be enough to take him down. Max out your specialty (Iam taking a guess that you are either a Smuggler or a Tech Specialist), with the appropriate perks (I personally love my Balanced TechSpec with offensive drone), and then I suggest decking out your PC with some heavy duty armor and Weapons
Here is my Gear
Equipment:
Melee Weapon: Saurmorian Hammer(Chaurmine Gift)/Plasma Tomahawk(Uveto)/JoltHammer(Emmy, Myrellion)/Predator Talons
Ranged Weapon: Saurmorian Railgun(Chaurmine Gift)/Blacklight(Uveto)/FZR Fire Suppresion System(Shekka,Tarkus)
Armor: Premium Armstrong Suit
Shield: Reaper Armaments Mark I Shield Generator
Accessory: Fenris-class Assault Drone, Version 2.0
Underwear Bottom: Hardlight Anti-grav Thong
Underwear Top: Hardlight Anti-grav Bra
If you have a balance between Melee and Range the Saurmorian Hammer and FZR FSS Combo is spectacular; if the debuff sticks, the juggernaut will lose get a stat debuff, and if he gets hit with the Saurmorian Hammer, the Juggernaut will suffer more damage and a higher chance of a critical hit.
This is if your a Tech Spec and my personal choice in abilities
L1 Attack Drone
L2 Charge Weapon
L3 Power Surge/Deflector Regenerator
L4 Thermal Disruptor
L5 Gun Tweaks/Weapon Tweaks (Personal Preference, However Charge Weapon gives the weapon you are holding energy perk, activating the Weapon Tweak ability on non-energy melee weapon)
L6 Charge Shield
L7 Second Attack/Shot (Again Personal Preference)
L8 Drone Control
L9 Boosted Charges