Depends, I guess??
I bought my very first horse a year ago, with only 4 years of riding under my belt and minimal lease experience. Best decision ever.
I'm training him (Got him rising 6, an oldenberg/andie gelding) on my own, with help of two coaches but on the ground. One of my coaches has only been on him a max of 2 full rides, and 3 half rides. Not bad for someone with next to no training experience!
But this is possible ONLY because he is super forgiving and generous. He rarely complains, and if I do something wrong or ask in a way that he doesn't understand, he never pulls anything funny.
So, I'm sold. I love Iberians and their crosses. The horses that his breeder breeds all have exceptional temperaments, and that seems to be a general breed thing.