Short answer: Aliya Resort & Spa is more popular than Water Garden Sigiriya based on review volume and major travel-site metrics.

Why — key evidence:

• TripAdvisor review counts: Aliya Resort & Spa ~3,675 reviews vs. Water Garden Sigiriya ~1,217 reviews. (TripAdvisor.com)
• Google/aggregate listings also show more reviewer activity for Aliya (Aliya appears widely reviewed across platforms), while Water Garden has fewer total reviews (example: Water Garden’s Google review count reported on aggregator sites is much smaller). (TripAdvisor.com)

Notes:

• “Popularity” can mean different things (number of reviews, search interest, occupancy, social followers). Here I used publicly visible reviewer volume on major travel sites, which is a common proxy for popularity. If you want a different measure (Google search interest, social followers, or recent occupancy/booking rank), I can look those up too.