For rares, sets and other items it doesn’t look bad but I noticed for the orange and deep red tones of these two types of items the difference is somewhat difficult to see when you search your for them in your tab.
This is exaggerated more when you have multiple uniques and/or legendaries besides each other in one tab. The difference between the hi-lighted and greyed out version is quite minimal (ex. searching for “legendary potential”).
I know in the past Diablo 3 had similar issues with their legendary items until players brought up this similar issue. Although for their green set items they put a sharp bright red line around their green sets items (which looked awful). But they eventually made the contrast better on legendaries.
This is a low-priority issue I’m sure, just wanted to give some thoughts before game is officially released. Having a slightly broader outline or glow to these 2 kinds of items would be most welcomed.