  High energy particle colliders have been in the forefront of particle physics
for more than three decades. At present the near term US, European and
international strategies of the particle physics community are centered on full
exploitation of the physics potential of the Large Hadron Collider (LHC)
through its high-luminosity upgrade (HL-LHC). A number of the next generation
collider facilities have been proposed and are currently under consideration
for the medium and far-future of accelerator-based high energy physics. In this
paper we offer a uniform approach to evaluation of various accelerators based
on the feasibility of their energy reach, performance potential and cost range.
