It doesn't depend on an external library for its basic functionality - it's an completely independent and pretty slim XS module. It offers more and more flexible transformations (and is supposed to eventually offer a lot more yet). The killer criteria for me - it antialiases drawing primitives and supports TrueType fonts via FreeType, also antialiased. It is very easy to generate high quality plots using Imager::Plot
(I used it for an interactive math report
f.ex). I found it pretty easy to work with, overall, and quite intuitive once you figure out in spite of the lacking documentation.
Makeshifts last the longest.