I use the desktop version on my iPhone. I like it, I like the layout, I don't like the app or the mobile site, have tried both.
If I open the page from Safari it works fine first off. If I then switch to another app or put the phone down for a while, when I go back into Safari to the MN open page it automatically opens in the app instead. I then go back to Safari and the page won't load - so I have to close the page, open a new one and navigate back to whichever thread I was reading.
It's a little thing, but it's irritating! iPhone 5s, Safari.