MakeUGC's strength is the cast
MakeUGC's plans are organized around actors: 300+ on the entry tier and 1,000+ further up, AI actors who hold your product, custom avatars of yourself, and voices in 50+ languages. If you run creator-style ads in several countries and want a different face and a native-sounding voice in each, that catalog is the reason to pick it, and the plans that include API access and batch variations make it practical at volume.
Blurbly has no casting catalog. For a creator-style clip it generates one AI presenter from your description, or uses a model photo you have the rights to, and the plan is built around showing the product. Its main output is product-led (the item on a counter, in use, opened, close up) together with listing images, which MakeUGC's pages do not describe.