I grew up in a family sponsored by Penn....and all I use now is Shimano.
Penn had their place, they build a Dynamite proof reel that will last a lifetime, but I needed something with a little more finesse. The 706z and 704z is a powerhouse in Florida, as well as the Spinfisher series.
With that being said I've had the same Ci4+ 4000 for at least 6 or so years now? Caught everything from 40" redfish to 6" bass, king mackerel and flounder, steelhead and carp. My father has Penn's that have caught just as many fish but they certainly don't take feel the same a few years in.
My 4000 is just now due for a line roller bearing, I did replace the drag 2 years in to carbontex washers. Same with Penn as the factory drag can lock up on you over time.
I own 4 Ci4s and sold all my FKs, they just don't feel as "loose", i also prefer the older style round foam knob instead of the newer "T" shaped rubber version
Absolutely worth the price, I take care and at least hit it with freshwater after saltwater trips, and clean/grease it once a year. I polish it with a bit of NuFinish and a Dremel polish wheel while it's disassembled