Let''s all of us be very careful about considering all liferafts
equal and the term ''liferaft'' a generic one. In fact, they not only range high/low on the functionality and build quality scales but they are typically manufactured for three customers: General Aviation (Pipers to biz jets), commercial aviation and marine use. (Rafts built for the large commercial carriers scare the hell out of me...but then, there''s little likelihood that an aircraft that must land at 120+ kts into the water is going to present me with an unpunctured raft).
Many GA types are extremely light because the aircraft are so weight sensitive, having only a single engine and struggling to carry the people and luggage that already must go aboard. These rafts are typically built of lightweight cloth, have one chamber, lack an inflatable canopy and floor, and ''full survival gear'', is a meaningless term that each manufacturer gets to spec except for a very few bits.
OTOH one manufacturer builds for both the GA (specifically, the high-end Biz Jet) market AND the marine market, and seeks to be the premium choice in cloth quality, build quality and design functionality in both fields. Consequently, there rafts are never as light as the FBO''s in e.g. Ft. Lauderdale rent out to weekend pilots heading for the Abacos in their Pipers and Cessnas (which is what I suspect is being described above). Practical Sailor repeatedly has awarded Winslow the top ranking in these raft tests (both GA and Marine) and, since they compare in price with Switlik and Givens, I''m not sure why one would buy any of the other high-end brands.
One last point: in Europe, rafts are mandated by some countries (e.g. France, which must have more offshore yachtsmen than any FOUR other countries, per capita) and so rafts are sold like VHF radios
in the U.S. - minimum but functional standards and sufficient features to qualify for a ''raft aboard'' check of the box. When you see e.g. a Zodiac at a great price, even after import duty and shipping costs, that''s why.
In rafts as in life, in my experience there aren''t any free lunches.