I'd probably go Cordyceps or something like PeakO2. The benefits on performance seem to be a bit more impressive in the areas "lifters" care about and there are more potential health benefits from mushrooms IMHO.
I supplemented with BA for a long time. I stopped taking it months ago and haven't noticed any changes. I expected my higher rep sets to end a little sooner but nope. I'm finished with BA. I haven't tried cordyceps yet but you guys are convincing me.
How are you using the ND 10:1? Do you take it every day or only training days? One 250mg pill or two?
It is important to keep in mind with BA the washout period takes a long time, similar to how it takes awhile to build up benefits. I'd wager it is quite common that with an adequate diet and training plan you won't be able to pinpoint an acute drop off in performance due to this gradual loss of benefit.
Beta Alanine is cheap so I don't think it is a waste, but also think it is more dependent on training style.
Regardless I'd wager you'll enjoy a good quality Cordyceps product even if Beta Alanine isn't for you, the suggestions above are solid.