Can't say I've ever contemplated this exact comparison.
But, now that you bring it up, I do think there is a slight difference of perception to my eye between the 1950 and Bettarini cases. I'm drawn to a brushed or flat finish on the Bettarini cases (whether SS or titanium) and I personally like the polished look on the 1950 case. Something about the sleek style of the 1950 that reflects the light so beautifully with a polished finish. Just my take on it.
I don't own a 1950 ... yet ... but, that style is hard to ignore.
Same for the Rads. The stylish Rad case is similar in the way it plays with the light on a polished case. Don't yet own one but I recently examined the 346. Even though I like the polished look on a Rad, the titanium 346 case is Very easy on the eyes. Very.
I have both brushed and polished Bettarini cases and I do actually prefer the brushed look on them.
My two Titanium PAMS are both Bettarini cases. As Erik mentioned, the subtle, subdued look of titanium is very appealing to me personally. And I agree with him in that I like variation in look and feel among my timepieces.
Lastly, to your point about regaining fondness for a piece after a time of separation. I can almost forget about some of my watches after a while but, when they finally find their way back out into the sun, I quickly remember why I fell for them in the first place.
Thanks for opening the topic.