I don't know about the 450 with yasnac but I used to work on an ev650 with fanuc . They build a really solid machine that can handle heavy nasty materials . We did a lot of heavy machining and extremely high precision parts on that mill and never had a problem in the 6 yrs I was with that company .
It's been a long time since I've worked with yasnac and that was on matsurra's but I liked that control about as much as I like fanuc , pretty straight forward and reliable