They're both equally nice, they just have different purposes. Bookcloth is a solid color cloth or has a specific design imprinted on it. The custom covers can be made using a single photo, the pre-designed templates on the digital center or a completely original layout designed by you.
Would I do every album I make as a custom coverset? No, because I only want to do them for the extra special albums, like a wedding or a special trip. But that's just my opinion. Most of my albums are the cloth covered ones simply because they're run of the mill what we did every year albums.