Any consensus regarding this ?
No.
Armory is great but it needs to keep up with the blockchain on the online computer and i'm always afraid the offline, old eepc, will just not boot at one point.
I have printed the recovery paper wallet, but still armory in the end is just so much more complicated and time consuming than the nano ledger.
So in addition to that recovery wallet, why not make a backup on 2 USBs and leave them in a sealed contained near your offline machine? The chances of everything failing at once is near impossible.
I'm wondering if I should transfer all my btc to the nano ledger or not.
This depends on the amount of coins that you are going to store. If we are talking about large amounts that I'd definitely not recommend it. I'm not familiar with Ledger Nano software (I have one, but have never used it). Is there an option to create a backup? What if the hardware itself fails? You have to consider these things.