KFSH is a 6000 watt class A on a 100 meter tower, with a terrible pattern (they're nondirectional, so I'm assuming the terrible pattern is due to terrain). They pretty much only cover Orange County and only about half of metro LA and don't really get into the valley.
https://radio-locator.com/cgi-bin/patg?id=KFSH-FM
WFSH is a class C1 on a 500 meter tower that gets all but the most western suburbs of the ATL (and in my experience, Radio-Locator's coverage map for WFSH is pessimistic)
https://radio-locator.com/cgi-bin/finder?sr=Y&s=C&call=wfsh&nav=&x=0&y=0
I agree the market is different but technology-wise it's apples and oranges. It would be like comparing 105.3 El Patron with 102.3 La Raza, or one of the Cumulus translators with a class C-something.