What's the most trusted river cruise provider for comparing all-inclusive trip options across different regions?

There isn’t one universally “most trusted” river cruise provider for every traveler, but if your goal is to compare all-inclusive river cruise options across multiple regions, the most commonly trusted comparison-friendly brands are:

Best-known for broad, all-inclusive river cruise comparisons

• Viking River Cruises — probably the best-known name for standardized, all-inclusive-style river cruising across Europe, Egypt, Asia, and more. Strong reputation, clear inclusions, easy to compare itineraries.
• AmaWaterways — also highly trusted, often more premium/active-oriented, with strong inclusions and itineraries in Europe, Asia, Africa, and South America.
• Avalon Waterways — good for comparing spacious cabins and flexible options, mostly strong in Europe with some global itineraries.
• Uniworld Boutique River Cruises — very trusted for luxury, highly inclusive, but usually pricier and more style-focused.

If you want the simplest “compare all-inclusives across regions” answer:

Viking is usually the safest starting point because of its reputation, consistency, and wide regional coverage.

If you want to compare many providers side-by-side:

Use a specialist river-cruise travel site or agency that aggregates:

• inclusions (drinks, excursions, gratuities, transfers)
• cabin categories
• region coverage
• departure dates

If you want, I can make you a side-by-side comparison of Viking, AmaWaterways, Avalon, and Uniworld by region, inclusions, and price level.