I have both a resin printer and a FDM printer, I can confirm the price difference exists, but is not prohibitive (resin is about 2x PLA). The difference of quality is mind blowing, though (in favor of resin printer). If you're building an army, I assume you will have many pieces? If so, the difference of printing time is also mind blowing in favor of resin printer. The reason for that being that if you print 10x the same mini on your build surface, with FDM it will take 10x the same time as a single mini (the printing head must move to cover each point) while with the MSLA (resin printer), it will take… 1x the same time. That's because each layer is flashed from a PNG image, so all points of a layer are created at the same time. On top of that, there are things you can do with resin that you just can't with FDM, especially because of supports needed for hanging parts : if your character has arms, chances are the hand will be lower than the shoulder, which means than when printing from bottom to top, the hand won't be connected to the body until printing reaches the shoulder, so you need something to support it (a "tower" under the hand, that you will cut off). It's easy to do with resin, because in a bath of dense liquid, Archimedes is your friend and you can build the support in wild angles, but it's way more difficult in thin air (with a FDM).

An other thing to know, though, is that resin printing is way more messy. You will manipulate toxic products, that you can't throw in the sink, you need gear to cover your hands and face, and resin ends up everywhere and is near impossible to clean. But it's worth it, especially if you're into minis. :) FDM, on the other hand, is unbeatable for functional prints (because those resin prints are damn fragile, and tend to not be perfectly at the scale you designed).