As you may be aware if you pay attention to my ramblings on Twitter or on Super Hero Time, Mighty Morphin Power Rangers was shot (mostly) on film and edited on tape, with the final masters on analog tape. (They may have switched to digital SD mastering at some point, but I'm not sure) All Japanese footage (including Zyu1.5, Zyu2, Metalder, Spielban, and Black RX) came from film prints sent from Toei until Gaoranger, which was the first digitally-edited Sentai. Starting with Power Rangers Samurai, the series switched to HD, with Saban using the same camera model that Toei started using with Shinkenger.
Since film for NTSC television is shot at ~24 frames per second (actually 24000/1001 fps), while NTSC itself is ~ 30 interlaced frames per second (30000/1001 fps), you have to get five extra frames for each second to keep the footage at the same speed. This is achieved by using a 2:3 pulldown, which is best explained by Wikipedia. Done properly, this telecine can be undone, giving you the full frames at the original 24fps frametate. This only applies to the raw telecine, and may not be possible when editing includes 30fps effects, bits where the footage is sped up or slowed down, or composite shots where one part of the frame is at a different point in the pattern than the other.
A close look at the Shout Factory DVDs for Power Rangers Zeo through Time Force (I haven't looked at Wild Force or any of the Disney seasons yet) show that the people editing the show did great on a technical level. The telecining itself is perfect (unlike Toei's telecines from the same time, which are a blended mess. For more detail, see AzraelNewtype's Adventures in Encoding post on the Over-Time blog).
Now, Shout's MMPR DVDs are different. Most of the episodes don't have clean telecining, as they are taken from the Saban International masters, and as auch are most likely NTSC>PAL>NTSC conversions. The few episodes that Shout had Saban Entertainment masters, like A Friend In Need Part 1, look as good as Zeo does. However, the Saban Entertainment masters for MMPR have the closed caption bubble and the TV Parental Guideline rating at the start of the opening, which may be why the Saban International masters were used for most episodes. Personally, I feel the better video quality of the Saban Entertainemnt masters more than offsets any annoyance caused by the bubble and ratings box. Unfortunately, Saban didn't think so, or feel it was worth the effort to make a new set of masters that only used the Saban International video for those few seconds of the opening.