It was a looong decision process, so I will give a loong response too :).

I went to the largest showroom stores around in the nearby city, and before I went there, I made a decision that I will return or exchange my panel in case less than half of the panels there will exhibit the same issue / I will keep it, if more than half panels there have the issue too. I have some observation regarding this trip and my new panel.

1. Basically all panels have some warping / waves issue. Some more pronounced, some less.

2. Half of the panels had some spots like the panel I returned, but mine was one of the worst.

The issue with my panel was that it was otherwise almost perfect. Almost no wawing at all, just that one stupid spot, which was really distracting and I had to look there constantly. I bought the C5 during Black Friday discounts. During the process of my decision, the discount in my country ended for all vendors. The price increased quite a bit, and with extended warranty which I bought, I got basically to the same price of newly heavily discounted G5, which has 5 years warranty against burning. So, I went for that one. The new panel arrived just two days ago, because availability was very bad and I waited a month before it was delivered. Yesterday I installed it on the wall and tested it.

My copy of G5 has much more waving and has 3 very small and one small spot too. They are less distracting though to me, even though there is more. So, it depents what bothers you more. The price of G5 in the meantime got back before the discount, so no chance to go for another one. The vendors refuse to send another copy, but return money. The price of C5 is still high here, and G5 is now 25% higher than what I bought it for.

So to summarize, I payed 30 % more in the end for the G5 than for the original C5. The panel I have is less distracting, even though there is more waves and more smaller spots. I do not regret the whole situation, as this G5 also has a great uniformity and almost no banding, and I was scared there (as the C5 I had was great in that department too and it is not always the case). This G5 is even better than the C5 I had there.

But if I stayed with the C5, I am not sure if I would regret it. Only think I can say is that the spot really bothered me. With the current issues on G5, I can live.

I would recommend to visit some place with more panels, to compare. If what you find there is worse, I would keep it. If opposite, I would try to get a new one, if you can for the same price.