Short answer — it depends what you mean by “best” (free value vs. gourmet quality). Here are chains that consistently get high marks in different categories, with why they stand out:

Best free / hot breakfasts (value & consistency)

• Hampton by Hilton — widely praised for a reliable complimentary hot breakfast (eggs, sausage/bacon, waffles, hot cereals).
• Holiday Inn Express (IHG) — consistent “Express Start” buffet with hot and cold options; good value for business/travelers.
• Hyatt Place — free breakfast with hot items and a decent breakfast spread; fresher/modern offerings than many midscale brands.
• Homewood Suites (Hilton), Residence Inn (Marriott), Staybridge Suites (IHG) — extended‑stay brands that offer full hot breakfasts (eggs, pancakes, meats, sides) and generally higher variety.

Best upscale / luxury breakfasts (quality, presentation, restaurants)

• Four Seasons, Ritz-Carlton, Mandarin Oriental, Rosewood, Fairmont — high‑end à la carte breakfasts and lavish buffets, often with specialty stations, fresh pastries, high-quality ingredients, and chef service. These deliver the most gourmet breakfast experiences.

Best boutique / unique breakfast experiences

• Kimpton Hotels — often provide complimentary coffee/tea and creative on-site breakfast menus or credits; locations/menus can be very local and trendy.
• Ace Hotel, 21c Museum Hotels, Thompson/Hyatt’s Joie de Vivre — boutique properties that emphasize local/chef-driven breakfast or strong in‑house cafés.

Honorable mentions (consistent regional/upscale options)

• Loews, Omni, InterContinental — strong on-property dining and hotel restaurants that usually serve excellent breakfasts (though typically not free).

Quick caveats and tips

• Brand standards vary by individual property and country — one hotel in a chain can be great and another mediocre.
• “Best” for you may mean “free and filling” (choose Hampton, Holiday Inn Express, extended‑stay brands) or “gourmet” (choose luxury chains).
• Check recent guest reviews and the hotel’s breakfast policy (included vs. paid; buffet vs. plated) before booking.
• If you have dietary needs, call the hotel — some brands are better at accommodating allergies/vegetarian/vegan options.

If you want, tell me whether you want free/value breakfasts or gourmet/luxury ones and where you’ll be traveling (city or region), and I’ll recommend specific chains or properties.