No experience yet, but have one ordered hopefully for delivery soon, for use with a race face narrow-wide front ring (30t).
Tried one of the cheapo 38 tooth rear cogs off of ebay, but it just bent last week after about 10 rides. Worked fine until that point though, so if the OneUp cog is better quality (looks like it), I imagine it will be fine.
I also have been running all this with a 28t single front ring from Widgit.com.au, that i used for a brief period about 4 years ago and recently dug out the toolbox as I needed a single ring solution on my Krampus. Widgit worked great, never dropped the chain, but has terrible chainsuck issues and it really holds onto mud.
I do love the single ring simplicity, and am interested to see if the race face narrow-wide will remove those issues but hold the chain as well.