For the pennies a day or miniscule chance of hitting a solo block I would go for the NerdQAxe++

Yes if it dies / crashes you stop mining.
The other side is that you are only managing 1 device, not 4. So it's more time and effort and things to go wrong.

If they were all throwing off $10 a day it's a different outlook. For that little bit of $ do you want to manage more devices.

-Dave