Hello, Steve.
I've found Adblock Plus very useful, as I cannot cope with the moving adverts, as they tend to give me migraine (any flashing light unfortunately has that effect on me)
I've used Adblock Plus for the eleven months that I have had the Hudl 2, and have had no problems with it until this week, when I had to reinstall it, as it had ceased to work (no idea why?)
It's functioning okay again now though!
So no, I can't think of any cons!