Palmolive is great indeed - excellent performance and pleasant scent. Arko, on the other hand - drying (for me), and the scent? Let's just say polarizing, and I'll leave it at that.
Palmolive is my favorite shaving soap stick. La Toja is nice as well. Speick smell too much like some old men that I know, even though it is a good performer.
I have Arko in a tub. It is fine stuff, but I like Palmolive better.
I have traveled Europe extensively this year, and brought Arko sticks for my main travel lather. While out there I picked up some Palmolive and had a chance to really give it a head to head comparo. For me, even though I liked the Palmolive scent so much more than the Ivory soap smell of the Arko, the Arko gave a head over heels better lather for my face. Much thicker and much slicker. So since shave comfort is more important to me than scent, I give Arko the win in my case.
It depends on your local water. With soft water, most shaving soaps(most, not all) will give you a very similar result so it comes down to the scent. With harder water, then you will see a difference in the quality. In this case, Arko is hands down the best of the two (I'm talking performance, not scent).
I do prefer Palmolive in terms of scent but Arko wins with the hard water that I have here.