I would agree with the very short life of Juwel T8 tubes, usually about a year before light output is significantly lower than as new. Shame I never took a photo of the fixture one new Juwel T8 and a one year old Juwel T8. The old tube is really really dim compared to new tube, give away is plants stopped growing and it becomes difficult to see things in the tank.🙁. Mind you Juwel tubes were considerably cheaper than Arcadia tubes.
As for Acadia T8 tubes, after one year possibly could judge old and new tubes, but basically little change. However after two years, obvious difference in brightness, between new and old, the light definitely a bit dimmer and yellowing on old tube. Two year old Arcadia definitely considerably brighter than year old Juwel T8 tube.
Now moved to Juwel T5 (with Juwel T5's) a couple of weeks ago, so nothing to report apart from pearling plants and monsterous growth.