Easy as ABC....
A. It's got to perform i.e. no skin burn or reaction and the lather has to last plus be slick and protective. Essential.
B. I have to at least not mind the smell - I went through a stage where I loved Arko for its performance then hated the stink and eventually came full circle being just fine with it.
C. It's really great if it smells good: I very much love the scent of rose and violet especially but if a soap really punches above its weight and price point and gives a good, comfortable shave then refer to A and B.
I approach all shaving soaps or creams with the same criteria whether artisanal or mass-produced. Price is a concern for me as I have to watch the pennies and remember that it's just shaving (which I do enjoy) and not S H A V I N G (OMG, this soiled underwear and coffee breath scent is just the most awesome everrrrrr plus the 25-time milled llama milk soap contains organic orangutan sweat moisturiser from uber-fairtrade sources and it makes my skin softer than a curry turd, and, and, and - yeah baby!!!).
Palmolive stick is great but I do love my Wickham's 1912 English Rose.