"Neon sign" has become a catch-all term, but true glass neon and today's flexible LED neon are genuinely different products with different costs, lifespans and use cases.
Traditional glass neon
Hand-bent glass tubes filled with neon or argon gas, lit by high voltage. Produces a distinctive warm, slightly uneven glow, is fragile, and has become increasingly rare due to the fabrication cost and skill required.
LED neon (neon flex)
A flexible LED strip encased in a silicone tube designed to mimic the look of glass neon. More durable, lower power draw, easier to repair since a section can be replaced rather than the whole tube, and now the standard choice for most neon-style signage.
Standard LED signage
LED modules used inside channel letters and lightboxes rather than shaped into tube form, the default for most illuminated storefront signage rather than a neon-look product specifically.
Choosing between them
LED neon suits decorative, retail and hospitality signage going for a neon aesthetic. Standard LED modules suit conventional channel letters and lightboxes. Glass neon is now mostly reserved for heritage or statement art pieces where authenticity matters more than durability or cost.