I hear you about the forever nature of changing fences. As you can see I have a fat horse and lots of grass. Her paddock, is very very low on grass itself so I'm forever moving the fence when she's ready to be moved along.
Warratahs can easily be made safe if you put the plastic caps on them. Standards can break their holders and become more dangerous than warratahs. I've found my horses have respected them and never bothered to play/use them as scratching posts. Any warratahs not in use in the paddock (I have some set up but have taken the actual fencing down) I've put tyres on top so they can't harm themselves - it works a treat!
I personally prefer warratahs over post and rail, as do a lot of my horse owner friends. Whilst p&r looks snazzy, it's harder to maintain - and all the wooden posts around my paddocks have slowly begun to be replaced with warratahs as a little miss won't keep her mouth off them. I got asked why I had fencing around a perfectly good fence a month ago - I explained that I wanted that fence to remain upright and not be chewn!!
I see you're also in NZ... I think from memory my warratahs were $6 something per warratah from CRT. I bought ten at the time and still have about four left in the shed - you don't need to go overboard as they're quite sturdy :)
♥ Seoul Searchin' for the Lovebug ♥