Well I've had my Ribble Endurance SL Disc since March of '21. I've put about 2500 miles on it so far and I'll highlight my experience below.
I ordered my SL with 105, carbon aero bars and custom paint. I've since swapped out 105 for a mix of SRAM eTap AXS components but that has nothing to do with the bike other than it's sort of a pain to run lines through the aerobar if you haven't had to route internal cables before. It's not impossible, just not as easy as a traditional bar/stem setup.
Anyway, the shipping experience is the only part you need to be concerned about. My bike came beat up pretty badly. This was not the fault of Ribble as it was thoroughly wrapped but clearly the shipper didn't observe the word FRAGILE on the box. The net result were a few pretty nasty scratches to the paint. The reason this became a problem is because Ribble could not provide me with the correct touch up paint due to the custom color option. They sent me 3 separate shipments of paint and none were even close matching the actual finish on the bike.
Beside that, the bike rides beautifully. Do note that I have not ridden the bike on the standard heavy Aksium wheels that it shipped with so I'm sure handling/ride quality may be a bit worse with those hoops. With modern wide carbon rims and 28c tubeless tires, it certainly is more comfy than a Tarmac SL7 or Emonda. I don't race but I could imagine those who do might prefer something a bit stiffer but it's perfect for me. I ride in A paced club rides and never wanted for more in terms of stiffness or agility.
Honestly, for the price, I'd say it's pretty hard to beat. You have plenty of options as far as saddle, finishing kit, groupset, wheels, etc. If you know your dimensions, you can make a pretty educated guess to the perfect spec for you. I'm 6' and went a sized L frame with a 110mm x 42 cm wide bars and frame fits me just fine. I wrench on my own bikes so shop support is not important to me.
Hope that helped.