I've heard that the Progressive Industry ones are top of the line.
RV Safety Accessories Inc
has them at a decent price:
30 Amp Smart Surge Suppressor - SSP30 are 89.00
50 Amp Smart Surge Suppressor - SSP50 are 118.00
30 Amp Portable EMS with Integrated Display are 230.00
50 Amp Portable EMS with Integrated Display are 315.00
I'm getting ready to order the 50 Amp EMS from them. I'm more concerned about voltage too low, pedestal wired incorrectly, so on so forth than surges only, so I'm going with the EMS..