I don't have the Dahon bag but have both of the Tern bags mentioned.
I don't think a rack will be a problem with the cover since I used to cover a Dahon Silvertip which is a much bigger bike.
Since the bottom is open the bike will drip as expected.
The cover is very compact but time consuming to implement.
The Bodybag is very big and has light padding.
I use it to carry a complete WTP Zodiac BMX bike with probably 6" of bag length to spare.
It is very easy to use but not very compact.
Both products are built better than the flimsy ebay/China stuff.
Their price is justified to me, no remorse.
Last edited by ttakata73; 04-07-13 at 12:42 PM.