I like that it has many different ways to do various things with regards to creating your own effects, you can make everything from simple texturing through complex lighting setups using just this one package! It's pretty much perfect in my opinion if you want something very specific done (like customizing lightmaps). The documentation isn't all too good either so there are often times when figuring stuff out gets rather tedious since most of their info seems geared towards someone who already knows what they're doing at least somewhat well or else assumes knowledge they don't have yet - which might be fine but definitely makes learning new concepts harder than necessary once again, especially because some tutorials seem to lack even basic steps sometimes :/. Great piece of open source tooling though no doubt about it; we've had great success making our projects run faster and more smoothly by simply utilizing its features without having to resort to other toolsets/technologies entirely while also being able to.