I have the furmann pl-plus II series.Really good in filtering noise and spikes.Also protects your gear from overvoltage.All my gear is hooked up trough this furmann.The II series are alot better then the older I series,alot more protection.These shut down when the voltage goes above 250V (in Europe the max grid voltage is 253V).And at start up they first check the voltage,if it's too high it won't start and will give an error.It also has a volt meter on the front,and 2 tubes you can retract with leds in them (so no more bulbs) and you can dim them.Great for dark stages.On the back is a BNC connector so you can hook a light (like on mixing consoles) which can be switched on or off.Very handy.
It's not the cheapest,but it will give you max protection,usually the rest are glorified power strips.Usually with a cheap net filter and if you're lucky it will have some VDR's that will blow as soon as the voltage is too high.