How about "both" sort of....
Now due to a very attractive sale at Camping world I just "installed" a Surge Guard by TRC (The company name on the box is different but it's TRC)
I used to have an older portable I got for shipping plus repair (needed new 50 amp outlet)
I stripped the plug and outlet off the old failed portable and transfered them to the new HW unit. Protected the terminals (They are exposed. I do not like exposed terminals so I protected them multiple layers of protection) and "Installed" it between my Hughes Autoforme (already"installed") and my Auto Transfer Switch.
The Install is same as the Autoformer so google the Hughes install kit.. Which I home made.
Works (So far) very well
NOTE
Park--Hughes--TRC Surge guard--Transfer
That way if the park is a tad anemic (next week has that issue) the hughes makes up for it so the Surge Guard passes power.
So far it's shut me down once. (Power in that park can be very anemic).
Fun 2 weeks. IN addition to doctor's appointments (2 different docs)
New cooling unit in fridge
New floor in slide out
Got rid of 15 year old cat-shredded couch
Serviced Front A/C (Read did not need it) Thanfuly a Coleman (Easier to service)
Mopped roof
Washed entire outside
Waxed Entire outside with "Ceramic Wax" (Easier than the other kind we will see how it works).
Tomorrow I change campgrounds
Tired am I.