Which suture leaves more scarring: dissolvable or non dissolvable?

I prefer the non-dissolvable, because those sutures are removed within a week. That leaves NO FOREIGN OBJECT in your skin. The dissolvable kind "dissolve" by stimulating inflammation. That can result in a longer healing period. Ask for non-dissolvable. 

but permanent sutures must be removed by a certain time after surgery (as determined by your surgeon) to prevent the stitch scars like Frankenstein's.  Dissolveable sutures cause reactions as they dissolve but they lumps usually go away.  Bottom line, the scar quality is often a reflection of the meticulousness of how the wound was closed and not what suture was used in closing.