I personally believe the strongest five seasons to date (in order) were:
1. Season 3 - Best cast to date with all the teams being somewhat lovable, great locations (all except Morocco) and terrific suspense. Never boring, the near perfect season
2. Season 6 - Highly underrated, and used to be the favourite for me. This season, despite having bad winners was perfect in every aspect. All locations were excellent, great suspense. Only downside were the early eliminations of both female teams and a predictable boot order
3. Season 5 - The season considered to be the all-around best. It would have been my best, if only they had visited more Europe. Everything else was amazing, great final 3, loved Charla, terrific. I found myself losing interest once they reached the Philippines, but it picked up on the final leg
4. Season 18: Unfinished Business - The best of the new era. Great all-star teams despite having so many return from TAR 14, nice locations, wonderful suspense and an all around high fun factor
5. Season 22 - It was a tough call, but this has to be #5. The locations this season were almost perfect, visiting less Asia, but I enjoyed Asia this time more than any other edition. It did lose some ground by Ireland, but overall, it was excellent. Great cast of teams, let down a weak finale.
Honorable mentions - Seasons 7 and 21