Two years ago on my Woodlore course we were issued with a OG bag, which worked without any problem. Last week I used my own DPM bag, and hadn't any problems with that either.
The foot end became a bit wet, but my sleeping bag inside was still dry when I checked. Don't know if it was wet enough to allow it leaking.
When I bought it DPM was the only choice I had, so I took it, although I rather had OG - but that's because I don't want my kit to be overly militairy. Back home I put my sleeping bag in it en turned on the garden hose. No wet sleeping bag.
Difference I noticed with the OG one is that the OG one feels thinner, less robust. But that might come due to the fact the OG I used on the Woodlore course was used intensively, and my DPM one was brand new (warstock) and never been used by anyone before.
Just my 2 Euro cent.