I have flown both also.
Etihad’s seats (as well as the age & comfort of the aircraft ) are a much better quality & overall service.
I ceased flying GF for EY a few years ago. GF withdrew so many routes & seemed to be in decline, being more of a regional airline. My last flight with them was an awful experience, with luggage being badly damaged & no care for the replacement of it despite me staying out in the dessert & having to return a few days later.
The aircraft was old, noisy, tired looking, service on the ground awful.
Etihad have new A345/6 & 773 aircraft.
I have flown the 346 & 345 to/from Australia in Pearl Class, they are really superb, this being an ultra lh of 15 hrs. The 773 to Bangkok only has 2 classes so Pearl is further forwards, quieter, & a good experience.
For the future Etihad seem to be well funded, 100 new aircraft ordered 100 options. They have a very young fleet, of the best aircraft in the sky, & a fresh approach. Consitency is important, so why gamble on an Airline that you really are not sure if there service will be on an old aircraft, or old style seating day by day?
Surely, especially in this economic climate, reliability & value, as well as a future looking & financially stable Airline, is & will be, the most important??