Can totally understand why anybody wouldn't care for the Mighty Mouse cartoons, don't care for a fair share of them myself personally. It is a very formulaic series, that got increasingly repetitive even early on, and too many of the cartoons are too cute and lacking in tension and laughs (even when the adversaries are nearly always the most interesting characters). Mighty Mouse himself is watchable but pretty one-dimensional and is not always used well.
1945 was a very prolific year for Mighty Mouse. It was also another pretty inconsistent year for him, though not as much as the previous year that featured two of his worst cartoons 'The Two Barbers' and 'At the Circus'. None of his cartoons from 1945 were thankfully on their level, lesser ones such as 'Raiding the Raiders' still managed to be at least okay, though none fit my definition of great. 'Gypsy Life' though comes close and do agree that it is one of the best of the whole series. Even non-fans of the series and characters are likely to find themselves pleasantly surprised.
Best asset as ever is the music, which is its usual lush and characterful self. Also excelling in enhancing everything going on between the cats and mice. The animation is equally great in quality, especially the backgrounds and landscapes, though the colours are also very attractive and never drab or garish.
While nothing is completely hilarious, there is hardly a shortage of gags and they amuse if more in the second half, some of them are remarkably creative by the series' standards. There is also a genuine sense of threat courtesy of the bats, without being too dark or too sinister. The story may be slight and predictable, but it engages and charms at least. Mighty Mouse is much better used than a lot of his previous cartoons, feeling more of a lead rather than glorified supporting character, and found myself admiring his courage and willingness to help.
However, there are few surprises here and the events are very formulaic and easy to figure out, the second half being fairly more of the same.
It does start off a little slow and would have liked a little more compelling personalities for the mice.
Overall, for this early stage of the series and the series overall this was quite well done. 7/10