Everything both ways is no doubt mostly subjective, but I'd bet you haven't driven a 570S based on it. No right or wrong answers here, but trying to explain how much better the 570 is by virtually any measure than the Evora to someone who hasn't driven it, is like trying to explain how much better the Evora is than the Cayman to the Porsche guys who haven't driven an Evora. The 570 is life changing, and with a $3500 decat and dyno tune, 100 more hp, it crosses into the realm of hyper car, fire breathing and all.
Spot on, I've never driven a McLaren of any type. I've no doubt (and never have) that the 570 in any configuration is superior to the 400 in any important objective or subjective measure, just as it should be. To further qualify that, as the price of a 430 approaches that of a base or near new McLaren, I too would have a very hard time justifying a 430 as currently presented. In fact, the 570 is the most likely upgrade from my 400 if the time comes. It's highly desirable. I've said so here on several occasions.
But I think it's pointless to compare them (400 & 570) since they're worlds apart given the huge difference in acquisition and running costs. Since the Evora goes such a long way towards achieving a refined balance for the driver it sounds to my ears that saying "the Evora isn't half the car the McLaren is" more like a backhanded slap than an objective measure. More so since a lot of us bought Evoras specifically to sidestep the costs of a McLaren.
There's at least a $100K difference in acquisition price (vs. 400). Any new McLaren is going to be 115 to 120% more expensive than the actual street price of an Evora. I should hope the McLaren is dominant in every category! But just as I'd question the notion that an Evora 400 is twice as good as a base Cayman (it's better but damn if I have the math to say how much) , I'm compelled to pose the same challenge when comparing a McLaren and a Lotus. Plainly I don't see it your way. Still, the 570 would have to be twice as good as an NSX or a 991 GTS because I have driven those and they are not nearly twice the fun to drive while they are close to twice the price, and I think that's the Lotus trick. Impressive street usability and impact at a reasonable price. 'More than twice as good' sounds objectively very difficult to achieve, especially if one is not in need of a 10 second car and is content with the Lotus' accelerative performance. But it's true, I haven't driven a 570 (or a 430) and won't have the opportunity unless I'm in the market again and they actually bring the 430 in.
With the unfortunate for Lotus but good for shoppers discounting, the 400 has become the bargain exotic it was intended to be. The 570 is more like the bargain 488, I'd think. I'm not sure exactly where to place the 430 given the speculation about any potential US price.