I have a totally dead silent chain.
When I ride through a half round underpass I can hear my tires echoing off the walls but not a hint from my chain.
I sneak up on deer and ride right through the midst of them.

It helps to have a perfect chain line, and for a perfect chain line it helps to have a Phil Wood or Miche crank bearing with adjustable cups.

As for a chain coming off easier with a biopace ring than a chain on a round ring, I don't see it.
My chain won't come off unless I loosen the chain tug and the axle nuts.

With a bad chain line and a too-loose chain, I can see a biopace throwing a chain before a round ring would, but with a good chain line and proper tension, no hay problema.

I especially like my biopace on hills, both uphill and downhill.

Going uphill, out of the saddle, the slight delay at the bottom of the spin let's me pull earlier, and I mash less and pull more.
I literally pull myself uphill.
I can do this with a round ring, but even easier with a biopace.

Coming downhill, I tend to ride slower than perhaps most of my fellow fixed gear riders.
Or so I think.
I don't have anyone with whom I can compare myself.
I see another fixed gear rider about once a year.
Anyway, I go slow enough downhill so that I can stop myself without a front brake or skidding.
Again the slight delay at the bottom of the biopace spin lets me put back pressure on the rising pedal earlier in the spin.

From the very first time I rode a biopace ring, it felt rounder to me than a round ring.
A round ring feels like it has more vertical in it than does a biopace.

I think if some of my fellow fixed gear riders rode a biopace without anyone pointing it out to them, they would describe the bike as unusually smooth, but otherwise a fixed gear bike.

If anybody comes to Bend, look me up in the phone book and I'll let you ride my bike.
I think you'll like it.