Cons: must check the field every day to make sure it hasn't come down for some reason - mostly horses running through it or becoming tangled in it!!
We don't have many problems with our electric fencing, but I would say make sure that the upright stakes you use to secure it are sturdy and well pushed into the ground. Make sure also that the fencing tape is secure and not loose and flapping around.
I have electric fencing in my ponies paddock so he cant get out to the other lush green grass! Poor fella! But anyway, he got out a few times, but then we connected it up to a huge charged fence, and he has never tried again.. tehe.. I'm scared to go near it, it would give a huge bang! (The charge is for the cattle in the other paddock). It also stopped him leaning over the fence to get to the other side.
I wouldn't recommend it by itself. We have electric fencing across the tops of our wood fencing and on our wire fencing. It can ground out easily and the horses can usually tell if it's working or not. It works great to separate paddocks and to keep the horses off of the fences when the neighbor kids feed them grass. Some places sell solar powered ones which are really cool. Only thing is we can't figure out how to turn it off to add more fencing to it You can't just unplug it. hehe.