Four and a half stars, rounding up to five because of how unexpectedly good it is. I'll skip to the bad parts, because there aren't many of them: The suit/armor design for the Rangers and the Zords look bad, like they are just really overdesigned with too much extra stuff going on and the Megazord in particular looks awful; the monsters (putties, Goldar) look similarly terrible, the art department really screwed the pooch; the fight scenes at the very end were poorly choreographed especially the all CGI fight between the Zords and the monsters at the end. Other than that this movie is actually pretty damn fantastic. It has great acting from the entire cast, Elizabeth Banks does go a bit over the top, but in a fun way. There is some great dialog that made me laugh from the opening scene all the way through the rest of the film, with a few good call backs, too. The cinematography and overall look and feel of the first 3/4s of the film was all superb (dives a bit with the final fight unfortunately). And each character got at least some character development, nobody felt left out or shortchanged. Honestly, there are sooo many movies where the special effects, costume design, and action sequences are the only good parts of the movie and all the rest (dialog, plot, character development, emotional connection, etc...) are either neglected or flat out missing all together (I'm looking at you Valerian! the most 'pretty but vapid' movie ever). I fully expected this to be one of those movies. Instead what I find is a legitimately entertaining and downright endearing story, with characters that feel real and relatable. This movie managed to make me care about these characters, that alone deserves 4 stars. If you watched the first 3/4s of this movie and shut it off once they finally morph into the armor, you'd probably walk away saying 10/10, five stars, three thumbs up.
I hear they've greenlit a sequel, let's all hope they can bring back this great cast, writers and director, and just bring in a new art/costume design team or special effects crew to redesign the enemies, armor and Zords, and maybe a better fight choreographer too.