The first two seasons of Super Sentai, Goranger and JAKQ, were Sentai's longest and shortest seasons respectively. Goranger was the longest with 84 episodes while JAKQ had 35. Since then, Sentai seasons had consistently had roughly around 50 episodes, give or take 1 or 2 episodes. Most Sentai seasons are typically longer than most Power Ranger seasons, with the exception of the first two seasons of MMPR and Zeo, which I will get to in a minute. While some long seasons can be enjoyable (especially with a good cast), sometimes they can have a side effect of having too many filler episodes or the story moving at a slow pace. These seasons can also be episodic, though if you ask me that's not necessarily a bad thing. I've seen this with both Sentai and Power Rangers.
MMPR S1 was PR's longest season with 60 episodes. Originally MMPR S1 was planned to be only 40 episodes long, ending at Doomsday. MMPR was also expected to be a one season flick like Kamen Rider Dragon Knight was. However, MMPR experienced unprecedented popularity, which forced Saban to ask TOEI to produce more Zyuranger footage (known as Zyu2). This extended MMPR S1 by about 20 episodes and the Zyu2 footage would also make up the bulk of the first half of S2's ranger footage. MMPR S1 did have symptoms of a long season, such as having many filler episodes and being largely episodic. However, IMO, many of the filler episodes were rather enjoyable due to the good cast that MMPR S1 had. MMPR S2 and Zeo were also 50+ episodes long. Eventually under the Saban Era, Power Rangers would be reduced to 40 episodes.
One comparison I'll make is Timeranger and Time Force, which I'll admit I'm somewhat schizophrenic over the two. Timeranger was 10 episodes longer than Time Force. For me, the first half of Timeranger suffered from the symptoms I mentioned above, moving at a slow pace. For example, Naoto and the City Guardians don't show up until episode 27, while their PR counterparts, Eric and the Silver Guardians show up in episode 11 or 12 of Time Force I think. However, despite the slower pace in Timeranger, it did a lot better job with character development than Time Force. All of Timeranger's major characters were well developed, while Time Force felt like there were only 3 characters that really mattered, Eric, Jen, and Wes, while Trip, Lucas, and Katie were kinda just there. Perhaps the stronger character development in Timeranger was due to having a longer season.
After the Disney buyout, Ninja Storm-SPD had 38 episodes. This was a slight cut from the 40 episodes that Lightspeed Rescue, Time Force, and Wild Force had. Because of the slight difference it's not really noticeable and therefore, Ninja Storm, Dino Thunder, and SPD are rarely ridiculed for being too short.
Starting with Mystic Force and lasting through RPM, the episode count on Power Rangers was cut to 32. This was likely due to a lower budget from Disney, and a move to cut cost. Many fans have complained that these seasons are "too short" and feel rushed. Personally, I think it's more of a problem with Bruce Kalish's writing than the number of episodes each season has. These seasons also lacked in character development in comparison to RPM.
Like Mystic Force- Jungle Fury, RPM has 32 episodes. I personally liked the shorter season. RPM had much better writing than the Kalish seasons did, thanks to Eddie Guzelian and Judd Lynn. There's a lot fewer filler episodes in RPM than most PR seasons, and the characters were all well developed early on. For me, RPM moved at a fast but steady pace, and keeps me more interested than a long, dragged out season like MMPR S3 for example.