I am in no way have any association with Ace but I used to go there a lot when I worked at San Mateo (next town over). I always had good service but have also seen potential customer just being looked at and neglected.

I kinda like the neglected part when I am just browsing item and just admiring the engines

It seems that if you ask for the big stuff (1/8 items) you will get their attention fairly quickly. When I both small items, I just point, grab the part, and pull out my wallet....but I understand that most don't have this luxury.