I like the 1.5 also. It's colors are a little colder than some of the other 50mm sonars.
I can't believe how cheap these, and other previous "cult" lenses have become. I'm glad I didn't hoard, and usually sold any extras I didn't use. But still have about ten 50 mm classics! These great 1.5 lenses are selling as cheap as the 1.8 now. It's funny, I just looked at the Soviet J-3 F1.5, in the cheap aluminum mount. Those are averaging higher than either! It used to be the J-3 was about $100, the Canon 1.8 about $150, and the 1.5 about $400. Now it's almost reversed. The Canon 1.2 used to be $900, I don't want to look, I have two. Looks like the Canon 1.4 is at the top of the price heap now.