I am certainly not experienced with every alloy out there. Here are my thoughts based on personal experience.

I love using CPM154 stainless steel largely because it's pleasant to work with. You can make the edge quite thin before HT (.010") without fear of warping if you have a skilled heat treater. There's also an alternative tempering range that leaves a bright finish on the blade. This means you can sand the blade to 600-grit before hardening and have very little finish work to do when it gets back.

The easiest to hone steel I've ever used is 52100. It just gets unbelievably sharp off of the Nakayama, quickly and easily. It's easy to grind, too. The downside is that the edge must be left thick before HT (.025"+) and it comes out of ovens covered in scale that must be ground/sanded off. I also have a hard time getting stock in the sizes I want.

Whatever you choose, the work will be difficult after heat treatment. You'll have to put the files away and sand the hollows by hand. For that reason, I waited until I had a grinder before attempting a razor (I made about a dozen knives with hand tools). Now that I'm more experienced, I've been going back to hand tools out of curiosity. For me, the easiest razor to make by hand is a simple kamisori. The ura side can be completely finished before heat treatment, so you only have to hollow the omote when the blade is hard.

Hope this helps.

Phillip