How do you judge?

Dilemma: how to decide whether something is better than something else.

An example: I have to decide on which version of Chapter 1 I should use for my novel. I can see the merits of both, and rading all the books and advice about story openings has helped, but I still have to decided which is the "better" version.

Another example: I have an idea for a new scene that I am considering adding to my mostly completed book. This scene is in part a response to comments from my critique group about wanting more on the culture and setting of my story, which takes place in a different country. I am the sort of reader who usually skips over descriptive passages about setting. My favorite thing to do when I read is to be inside the heads of characters, to know what they think and how they feel. Not having a strong visual imagination, I don't really need to "see" too much of my characters' surrounding when I read.

Two things are making me lean toward adding the scene. First, I found myself enjoying passages about setting in a recent book I read. (Thanks, Laura for the beautifully written Red Glass.) http://www.lauraresau.com/index.html That can mean (a) even someone like me can develop a stronger visual imagination, (b) the author is highly skilled (c) it is possible to weave setting into a story that doesn't call all attention to itself but draws the reader into the world.

Second, the possible new scene shows the protagonist doing something that puts her into more trouble. Previously, I allowed only her best friend to get into this particular trouble but I think I need to let my protag make this unwise decision so she can be more believable.

Seems that I have good reasons to add. So why am I hesitant? Maybe it's because I am not totally convinced that it's a good addition to the story, or because it will add words to a work that is already on the long side, or because the writing of the scene is not going smoothly. Then there is the little nagging thought that maybe I keep wanting to add or tweak scenes because I'm afraid to acknowledge the book needs to go out to the world--and be judged. (Ah, fear, rearing its ugly head again.)

Sure I will ask for comments from trusted readers, I will set aside the work so I can look at it with fresh eyes. But in the end, I need a basis on which to make my decision, sans all the emotional baggage and nagging thoughts about what-ifs.

Is an objective decision possible?