Catalog dress-up apps
Quick avatar builders assemble a character from their own parts library. They are a fine first step, as long as what you want exists in the catalog.
LAS is not limited to a catalog. It builds from any base or outfit you own, in your style.
The do-it-yourself Unity route
Most custom avatars are made in the Unity editor with tools like Modular Avatar and VRCFury. It is powerful, and it is also a steep climb through inspectors, rigs, and shader settings.
LAS drives that exact pipeline for you. Same result, none of the learning curve.