One problem with MOVs is that they will eventually fail. That is what they are designed to do - "absorb" the spike and dissipate it as heat, to the point of failure. And you will not know when they are going to fail.

MOVs backed up with a true “lightning arrestor” are the best option. If you can still find surge suppressors with gas-tube lightening arrestors and MOVs, you have a good combo. The gas tube will fire (like a florescent tube) sending the surge to the ground wire before the MOV can fail. The MOV will suppress the small spikes.