How does this compare with the Viking Arm lift that does the same things but is twice the cost?

We cannot speak on the Viking Arm as this is not our product. We can provide the information on the IRHT83100. Product Features: 300lb of Sustained Clamping Force achieved with trigger handle; 825lb of Sustained Clamping Force achieved with screw handle Glue Resistant Pads for easy cleanup and to avoid damage to the clamp and/or workpiece Quick Change Mechanism to easily convert to a spreader Coupler for combining two clamps for extra length Hex-Bolt on screw handle for additional leverage