Yes, it's a well-produced ambient. My suggestion would be to keep the rain sound out of the music, however, because rain in a map is likely to be added via a separate environmental sound, and leaving the music "clean" will make it more widely usable in maps which don't actually include rain.
If you want to get into producing ambient sounds for mappers, I recommend learning about Doom 3 sound shaders and how to make them out of looping sounds (with an optional lead-in which plays before the looping part). If you distribute your ambients as pre-made sound shaders, mappers can just drop them straight into a map without needing to do any extra work.
I wrote a tutorial on how to do this using REAPER, but I imagine the technique for creating a seamless loop in Reason is very different (and perhaps you already know how to do it anyway).