I’ve spent tens of billions doing abyssal mod rolls, of all levels.
Decayed is a waste of time and money. Gravid and unstable has the potential to have some benefit but the high cost and high chance of receiving nothing worthwhile makes it barely worth the bother.
Abyss mods would have been more useful if they hadn’t caved to the whiners and nerfed abyss items prior to launch. Even decayed would have been at least worth trying.