Short answer — it depends on what you need (search, book, track, or get help). Best overall workflow: search broadly with an award‑search tool, confirm availability and price on the airline/partner site (or through your transferable‑points portal), then book (or hire a concierge if it’s complex). Below are the best platforms by purpose, with pros/cons and quick recommendations.

1. Airline & partner websites — best for final booking

• Examples: United MileagePlus, Air Canada Aeroplan, British Airways (Avios), Alaska Mileage Plan, American AAdvantage, Delta SkyMiles, and the loyalty sites of the airline that issues the award.
• Why use them: they’re authoritative (lowest risk of “phantom” inventory), let you complete the redemption and manage the ticket, and sometimes reveal member-only inventory. Always confirm and, if possible, book on the airline or the airline’s partner site that shows the space. (thepointsguy.com)

2. Award‑search engines / tools — best for broad, fast discovery

• Point.me, Roame.travel, PointsYeah / Seats.aero, AwardFares, AwardHacker — these scan many loyalty programs and show which program can book a routing and how many points it costs. Use them to compare options and find “sweet spots.” Roame and PointsYeah tend to be faster/more flexible; Point.me is feature‑rich but slower. (nerdwallet.com)
• Pro tools for power users: ExpertFlyer and KVS Tool show award buckets, fare classes, and let you set alerts; useful for upgrade searches and very specific inventory monitoring. (ExpertFlyer is paid.) (expertflyer.com)
• Caveat: third‑party tools don’t always see everything and can show false positives or miss inventory — always double‑check on the airline/partner site before transferring points. (frequentmiler.com)

3. Transferable‑points portals & bank booking tools — good when you have flexible points

• American Express Membership Rewards, Chase Ultimate Rewards, Citi ThankYou, Capital One: these let you either book directly through a portal (cash + points options) or transfer to numerous airline partners to complete award bookings. They’re often the quickest route if you already hold transferable points. Always verify partner pricing/availability before transferring. (thepointsguy.com)

4. Award‑booking concierge services (paid) — best for complex itineraries / time savings

• Examples: PointsPros, Juicy Miles, Point.me concierge, BookYourAward/Cranky Concierge and similar services. They research partner options, handle transfers and booking for a fee — a good option when you lack time or are trying for complicated multi‑carrier routings. Fees vary by provider and complexity. (pointspros.com)

5. Account & award tracking tools — keep balances and alerts in one place

• AwardWallet and similar services track balances, award expirations, and can store alerts. They’re handy to avoid losing points and to know when transfers complete. (en.wikipedia.org)

Practical, prioritized recommendation (most users)

1. Start on an award‑search engine (Roame or PointsYeah for speed; Point.me if you want guided transfer info). Use Google Flights or ITA Matrix to check schedules/routing possibilities. (roame.travel)
2. When you find a candidate routing, confirm it on the airline or the airline’s partner site (this avoids phantom space). If it’s bookable and you need to move transferable points, do so only after confirming pricing and transfer times. (thepointsguy.com)
3. Set alerts (ExpertFlyer, KVS, or the search‑tool alerts) for routes you want. If you can’t find availability or itinerary is complex, consider a paid concierge (PointsPros, Juicy Miles, etc.). (expertflyer.com)

Quick pros/cons summary

• Airline sites: authoritative, best to finalize bookings; sometimes harder to search across many programs. (thepointsguy.com)
• Roame/PointsYeah/Seats.aero/Point.me/AwardFares: fast cross‑program searching; may miss or misreport some availability — always verify. (roame.travel)
• ExpertFlyer / KVS: detailed, alertable, for frequent flyers / upgrade hunters; paid. (expertflyer.com)
• Paid concierges: save time and can unlock complex routings, for a fee. (forbes.com)

If you want, I can give a short, personalized checklist for your next booking (which of the above tools to run in what order, what to verify before transferring points, and which concierge to contact for your route).