My two cents. Our fifth wheel had a hard wired Progressive Industries 50 amp EMS. In the 4 years we had the trailer, it identified a power issue twice, and shut power down to the rig BEFORE anything bad could happen.
When we bought our WhiteHawk, the first thing I bought and installed was the 30 amp hard wired model of the Progressive Industries EMS.
The hard wired models are more expensive, about $250 for the 30 amp, $300 for the 50 amp. Those prices include the remote display feature that also features a bypass switch. The Progressive Industries device not only protects against a power surge, but also will recognize several other potentially damaging/dangerous power faults and automatically cuts the power to the RV.
I prefer the hard wired model vs. the plug in type for two reasons. One, the unit is not out in the weather, & two, no theft worries. The hard wired models are easy to install, only took me about an hour. Great, American made product with a LIFETIME warranty.
There are many RV dealers and online retailers that sell them. Tweety's & Lawrence RV Accessories have the best prices on the Web I have found for Progressive Industries products.
Good luck with your choice. One of the best improvements you can make to your RV IMHO.