What 50 amp surge protector do you recommend, and why?

You want an EMS not a surge protector.
I have and like the Progressive Industries EMS units. Mine is right after my autoformer before going into trailer. A rising star is the Hughes Power Watchdog combined with the Hughes Autoformer. The combination protects from low voltage as well as all the benefits of an EMS.

You want a unit that will provide surge protection as well as protection against high/low voltage, reverse polarity, ground faults and a display that will provide information on any problems at the pedestal and a readout of voltage/current.

Some hardwired units (installed in the RV) will have a remote display so you can locate the display in a convenient location to monitor the status. I have a Surge Guard unit but one thing I like about Progressive is there is a way to bypass their EMS if a problem develops with the unit. You can bypass the hardwired unit and substitute a pedestal mounted unit until you can have it replaced.

fj12ryder wrote:
We have the Progressive Industries 50 Amp and are very satisfied with it. We had two SurgeGuard units before the PI and both failed, one pretty spectacularly. Water intrusion was their downfall.

The PI has been going strong for about 3 years now.

I agree with the brand, but would suggest a permanent install.

Link

PI HW50C, same one since 2004.

THE MAIN PROTECTION FOR ANY 50A RIG IS PROTECTION FROM AN OPEN OR PARTIAL OPEN NEUTRAL.

First trip after installation we had 160V at 10:30PM on a 30A pedestal, not common but it happened.

So what was the cause?

We have the Progressive Industries 50 Amp and are very satisfied with it. We had two SurgeGuard units before the PI and both failed, one pretty spectacularly. Water intrusion was their downfall.

The PI has been going strong for about 3 years now.