I would only want one, maybe 2 max, in my collection. I prefer the 1950 case over the regular Luminor case though, but I'm positive I don't want domed crystals to dominate my Panerai collection.
If I had 10 Panerai's and I had to choose between all regular flat crystal or all domed crystal, I'd opt for all flat crystals. The domed crystal is a nice novelty but I think I would get tired of it if I had to look at the distortion everyday on every one of my watches.
Just my 2 cents,
Anthony