I just got my Launch 4. It's replacing a Ken Onion Chive so size is just about the same but the handle is significantly thicker. The release button is very gritty feeling if you press it slowly but it feels like it's wearing in and getting smoother. This is my first auto so I can't say much for how it compares to others.

Pros:
I really like the small size.
It locks up tight with no play when open.
$69 and it feels like a quality knife.

Cons:
I wish it would have been sharper out of the box.
I wish it came with a "deep carry" clip so it would sit lower in my pocket.
Button is not smooth.