Asus laptop - older model more ex?

[VanquishShadow]

Am shopping around for a replacement of my Zenbook UX31A. I love the notebook but the memory has some hardware issue and crashes intermittently, and from what I read, the RAM is soldered and can't be replaced easily.

Hence, looking for:
<$1500
min 14" FHD matte IPS screen
SSD
backlight keyboard
SD card slot
USB C port
discrete graphics will be a plus

Been around to various retailers, and at Best Denki I was puzzled to find that the older UX410 model was more expensive than the newer UX430 model and even the larger VivoBook S15

Specs:

UX410UQ-GV015T (silver colour)
i7-7500U
8GB DDR4
1TB SATA + 128GB SSD
GeForce GT940MX 2GB DDR3
14" FHD
$1598

UX430UQ-GV047T (silver colour)
i5-7200U
8GB DDR4
256GB SSD
GeForce GT940MX 2GB DDR3
14" FHD
$1298

S510UQ-BQ176T (gold colour)
i7-7500U
8GB DDR4
1TB SATA + 128GB SSD
GeForce GT940MX 2GB DDR5
15.6" FHD
$1298

Based on this, the oldest model - the UX410UQ is the most bo hua one. How does that make sense? Am I missing something?

And it seems like the S510UQ is a good deal when put alongside the other, other than the fact that it's a bit bigger and heavier.

 

[VanquishShadow]

also saw on haichitech the following

UX430UQ-GV163T (blue colour)
i5-7200U
16GB DDR4
512GB SSD
GeForce GT940MX 2GB DDR3
14" FHD
$1598

which seems a much better deal than the UX410UQ if I were prepared to spend $1.6k (except for the blue glossy lid which is a bit of a fingerprint magnet)