Not so long ago people in bookstores would reject a trade-published book for being self-published simply because of the glossy lamination on the cover. Now both Lighting Source and CreateSpace offer matte lamination, so the people who dislike self-published books will have to find other criteria.
Whether you select matte or glossy lamination for your book really depends on the particular cover. I’ve seen one book with a hot pink cover that is absolutely stunning.
I tried a matte cover on one of my books and immediately switched to gloss. The matte lamination made the green background too dark in indoor light. Outside in natural light the colors faded.