When I got my race bike I knew, I will convert it to 1x11 from 2x11 it came out of the box, but I was not sure about the oval or regular narrow wide.
In the end, I choose absoluteBlack oval chainring and I'm really glad I did so. It really makes a huge difference on technical sections and feels almost as a regular chainring everywhere else.
So basically when pedaling on fire roads, tarmac and fast hardpack single tracks I can't feel any significant difference while comparing to the regular chainring. The cadence is smooth and power feels equally distributed through full stroke just like on the regular chainring. But once you get at a steep climb, hard technical sections or deep sand, that is where oval chainring really shines.
Oval chainring works by changing chainring diameter during pedal stroke 4 times per revolution. This means that for 34t oval chainring it feels like pedaling 36t on downstroke but 32t when the pedal is at 6 o'clock, this helps to get past dead spots with ease and keep smooth cadence.
From my experience- I was not able to conquer climb or plow through the sand only because my pedals got stuck at the dead spot and I did not have enough power to pass through them, now my main problem is keeping balance and traction since my oval chainring almost eliminates completely those dead spots.
Durability and Performance
I have tested absoluteBLACK oval chainring with m8000 XT rear derailleur with clutch and XT chain which I changed to KMC X11EL chain later. Chainring performs spectacularly, I have 0 dropped chains even riding in deepest mud when I already have problems with skipping gears on cassette due to mud on it.
I have ridden oval chainring for almost 2000km and I won't be switching back ever.