"My series is better because its from my country."
This is one cultural bias that tends to go both ways. A lot of American Power Ranger fans will refuse to watch Super Sentai and sometimes ridicule the series because it's not American. While some Japanese/Asian Super Sentai fans have the same sentiment, and also at times criticize Power Rangers for "copying" their show as a "rip-off." These assertions from both sides are utterly ridiculous and indicate closed-mindedness.
"I don't like how long/short the other show's series or story arcs are."
This tends to be a fight between Zordon Era Power Ranger fans against both Sentai fans and Post-Zordon Era Power Ranger fans. In Japan and Asia in general, the most successful shows are the ones that have a one-year plot, and change cast, characters, suits, and themes every year, or are one year flings. This leads to Sentai and some Post-Zordon Era Power Ranger fans ridiculing the Zordon Era as too long and often ridiculing Power Rangers for having recurring characters that comeback year after year such as Tommy Oliver. This is also why many anime and jdorama's are no more than a year long in Japan.
In the United States, its the opposite. It is likely that if a show is successful one year, it will likely have a second and sometimes many many more seasons. Thus, a successful season in America is one that has continuity year after year or has a sequel. This is true for other American kid shows such as Ninja Turtles, Spider Man, X-Man, and Batman. Americans always want to see a good show continue. This often leads to Zordon Era Power Ranger fans ridiculing both Post-Zordon Era Power Ranger seasons and Super Sentai seasons as "too short," and is also the reason why it took Power Rangers a rather long time for it to adapt Sentai elements such as changing the cast, characters, themes, and stories every year. Thus when Lightspeed Rescue debuted it was unpopular at the time because it severed virtually all connections with the previous 7 seasons. This to me seems to be more of a misunderstanding of cultures than anything else. I think if both sides could get a grip on the cultural differences, this one wouldn't be much of an issue.