Add me to the list of people who are more fond of the concept than the execution.

I almost put Hedorah at Number 10. If I were expanded the list to 20 Monsters - He'll clock at 11.

Early Movies of Godzilla

Rating per Movie - 1/5 (Poor) to 5/5 (Excellent)

Godzilla (1954) - 4/5 - The Original - 5/5 For the Raymond Burr Edition.
Godzilla Raids Again (1955) - 3/5, has a nice human story, nicely done in style.

King Kong Vs. Godzilla (1962) - 3/5 - Epic Adventure, kind of documentary style movie
Godzilla Vs. Mothra (1964) - 4/5 - One of the better ones
Ghidrah, the Three-Headed Monster (1964) - 4/5 - One of Godzilla's toughest opponents
Godzilla Vs. Monster Zero (1965) - 2/5 - It's was okay, It was silly seeing Godzilla dance in this movie.
Godzilla Vs. the Sea Monster (1966) - I did not see this movie. Can't Rate it.
Son of Godzilla (1967) - I did not see this movie. Can't Rate it.
Destroy All Monsters (1968) - 2/5 - Kinda lame too many monsters and the script was poorly done.
Godzilla's Revenge (1969) - 1/5 - It was the poorest movie made. Some thought it was okay.

Godzilla Vs. Hedorah (1971) - 4/5 - One of the most unusual movie ever made and Hedorah was tough to beat.
Godzilla Vs. Gigan (1972) - 2.5/5 - It was okay - but I wished it was done better.
Godzilla Vs. Megalon (1973) - 2/5 - I never really cared for this movie at all. I wished I hadn't watch it.
Godzilla Vs. Mechagodzilla (1974) - 5/5 - One of two favorites in the 60's and 70's - Awesome Special Effects.
Terror of Mechagodzilla (1975) - 5/5 - My Favorite Movie of all time - Good Script and Great Special Effects.

My previous list did not include the 2014 version, this one does.

1. Godzilla (1954)
2. Godzilla, Mothra, King Ghidorah: Giant Monsters All Out Attack (2001)
3. Mothra vs. Godzilla (1964)
4. King Kong vs. Godzilla (1962)
5. Invasion of the Astro Monster (Godzilla vs. Monster Zero, 1965)
6. Ghidorah: The Three Headed Monster (1964)
7. Godzilla vs. Destroyah (1995)
8. Terror of Mechagodzilla (1975)
9. Godzilla Against Mechagodzilla (2002)
10. Godzilla vs. King Ghidorah (1991)
11. Godzilla vs. Mechagodzilla (1974)
12. Godzilla vs. Mechagodzilla II (1993)
13. Godzilla: Tokyo S.O.S. (2003)
14. Godzilla vs Hedorah (1971)
15. Godzilla (2014)
16. Destroy All Monsters (1968)
17. Godzilla vs. The Sea Monster (1966)
18. Godzilla Raids Again (1955)
19. Godzilla vs. Megagurius (2000)
20. Godzilla vs. Biollante (1989)
21. Son of Godzilla (1967)
22. Godzilla 2000 (1999)
23. Godzilla Final Wars (2004)
24. Godzilla's Revenge (1969)
25. Godzilla vs. Gigan (1972)
26. Godzilla vs. Space Godzilla (1994)
27. Godzilla vs. Mothra: Battle for the Earth (1992)
28. Return of Godzilla (1984)
29. Godzilla vs. Megalon (1973)
30. Godzilla (1998) referred to contemptuously and correctly as "Godzilla in Name Only"

And a few more:

Godzilla's Revenge is my favorite bad movie ever ... and I'm honestly not sure that it's bad! Weird, yeah. A bit off in the common sense department, yeah. Way off in the dubbing department, sure.

I've probably seen it more times than any other Godzilla movie except King Kong vs. Godzilla.

You and I are in the same agreement - I seen it twice and vowed never see it again!