I just copied/pasted then modified this from my original post from my Super Sentai blog. I hope this can help stop the severity attacks from both sides.
Now here are the things that are found common in Super Sentai and Power Rangers. I can't list them all though.
The most obvious has to be morphing sequences, color coding, those really warm suits and the shows are just filled with so much weird science. Not to mention both teams rely on teamwork to do the job assigned to them despite differences although PR takes it to another level with different ethnicities but there's not much culture clash.
Both shows have wacky moments with the rangers but in Sentai, it seems to happen a lot more. Also there are more wacky photos in Super Sentai among its cast members than in Power Rangers among its cast members.
Some of the men really need a haircut like Tommy and Andros from PR and Eiji from Sentai to name a few. Since Tommy cut his hair, well looks like Eiji and Andros can start a good conversation.
The problem of too much red ranger focus can happen also. Besides I believe Jetman and Maskman are a few Sentai series to have that weakness.
Both shows can have face value heroes and heroines, who at times are unusually gorgeous. Kimberly Hart from MMPR was the prettiest PR character and in Sentai, I count that would be Jasmine from Dekaranger. IMO Kimberly Hart is >>>>> to Jasmine in terms of being hot but I like Sentai more. LOL. Should I mention about the short skirts and short short pants?
Both groups fight a certain enemy attacking their respected places although Power Rangers' villains are less menacing than Super Sentai most of the time. Since both shows tend to copy each other's ideas and modify them, so the evil rangers in both versions do exist but at times, they exist with a separate story.
Both shows mix a certain amount of humor with seriousness although with Power Rangers, seriousness is being reduced due to U.S. show standards. These days, it seems Super Sentai shows a greater amount of humor and seriousness than Power Rangers.
Both shows get criticized for violence but Super Sentai more so.
There are good writers and bad writers involved in both franchises.
In times, both shows have their own romances whether it be the heroes or the villains.
There is always a circulation of original ideas that happens between the two. Some things Sentai had, PR ported it and later, the opposite happens.