Delta Panniers

[sachmo]

Hello all,

I'm looking for panniers for day-trip cycle/hiking missions in the blue mountains, Australia...

They need to:
- convert to a back pack
- be waterproof
- not bounce around on moderately bumpy tracks

I've seen a few converting panniers online (including Arkel and Panpack). The Delta backsack is another one (http://www.deltacycle.com/cargo/bagsframe.php?bodypage=backsack.php&nav2page=bagsnav.html) but I can't find much info on them - DOES ANYONE KNOW IF THEY ARE ANY GOOD?
cheers