The only hardwood I've used is ash, from Allegheny Mountain Arrow Woods. I like ash a LOT. It offers good mass for my trad and selfbows, stains beautifully, is inexpensive compared to other woods, and is very durable. This last is critical for me here in the Rockies as I do a lot of roving amongst all those rocks.
Ash is hard enough that it requires heat to straighten, which is easy enough to do -I use a heat gun. I also use an arrow straightening "wrench" too, for any tighter curves. Mine is simply a 3/8" piece of hardwood with a hole drilled through it. Ash stays straight after heat straightening.
I cannot think of a downside to ash, unless you are shooting light bows and/or a hunting weight bow in which you want to go under 10 grains/lb draw weight. I shoot for 11 to 12 grains/lb. in my big game bows (50 to 60lb), and ash is perfect for this. For my light bows I use Sitka.
I really like Allegheny Mountain too. They've been very easy to work with, supplying test shafts (3 spine weights), and shafts within a certain weight range to match draw weights of certain bows.