We've been showing huge composite buildups done in lieu of crowns. Here is two composite buildups in function that have held up.
Both these ladies could have afforded crowns, but both choose composite buildups. This shows that you can confidently recommend composite buildups as an alternative to crowns when there's a significant amount of solid tooth structure remaining. I do not believe that these can hold up as long as a crown will (a really well done one and we all know how that story ends). Still there are a multitude of scenarios that we encounter where, for whatever reason, the crown option is not available.