Panniers vs Bikepacking Bags

I've just used the Blackburn frame bag, medium sized, on my medium Marin Pine Mountain. Really liked it. Seems very well made.
Unfortunately it meant I couldn't use the bottle mounts in the triangle but luckily I have mounts beneath the downtube too.

I also have the Podsacs bar bag which essentially works really well. The fitting depends on cabling etc really. I didn't like having to squish my cables to fit it but it didn't cause any issues.
I might look into getting a bar with an extra loop such as the Sonder Confucious.

For the seat pack, I just used a dry bag and two loops of hook and loop straps. Worked pretty well.
I've got a Blackburn outpost seat harness coming off eBay though.

Rode over three days with my tailfin aeropack on the north downs, king al's and South Downs way, did not fit the mini panniers as decided to glamp due to the thunderstorms forecast.

Aeropack was totally solid off road with some fast bumpy trails, so a recommendation from me.

I was in the Brecon Beacons when the self supported offroad LEJOG race passed thru, loads of them had a tail fin and I guess they should know