In most cases, I prefer to gel. I like the darker more translucent look of the bar, I find molding quicker and easier, and I feel confident that saponification is well underway. I find that my gelled soaps are less prone to ash. Also if I'm using an FO that is a known accelerator, or milk or any additive that contains high sugars, I'll gel because it will probably happen whether I like it or not.
However I don't gel if I'm attempting mounded textured tops (they will flatten somewhat during gel) or if I'm using a fragrance with a low flash point or a tendency to morph or burn off. For example, when using citrus EOs, I suppress gel so more of the scent remains intact for a longer period. A few months ago, I made an ungelled soap which was mostly 5x Lemon EO anchored with a bit of litsea, patchouli and a few other things. I did get some ash but the scent is still strong and true.
Either method will yield good soap in the end.