Good question, Hidious. I only got into record collecting 2 years ago. I grew up on records with my parents but like most kids my age, I began collecting cassettes and then eventually CDs. Anyway, a few years ago I ended up finding a great condition copy of Judas Priest's "Defenders of the Faith" on LP for a dollar at a yard sale, and soon began the journey of collecting vinyl. I started with collecting just Priest, as they are my favourite band, but then as I started listening to them, I noticed that these songs somehow sounded different than what I remembered on CD. They sounded "fuller", or more complete. So I guess, the first reason I collect vinyl is that yes, the sound is better.
The second reason, one that you didn't mention, is obvious: the record jacket/cover. When you have a great album cover (like Kalmah's 12 Gauge), it looks so much better when it's 4 times bigger than CD cover!
So these are the 2 main reasons I buy vinyl. In the case of this Kalmah record, the rarity certainly sweetens the deal, but is not the reason I bought it. I would say that the limited to 500 run was the reason I rushed to buy it immediately upon release, because I thought there would be a lot more demand for them.
Some notes about collecting and listening to vinyl:
- sometimes scratches or dust can ruin the listening experience.
- they cost more to ship (ordering online is pretty much the only way to buy records these days)
- with new releases check to ensure that the album was actually mastered for vinyl. If not you could end up with a digital recording on vinyl, which completely defeats the purpose!
- storage can be a pain; they are big/bulky and have to be stored upright like books, never flat.
Let me know if this piqued your interest and you actually start buying/collecting!
Cheers.
It actually inspired me to start a vinyl collection of some of my favorite metal bands and now I have about 30 or so... here is some of them, not the clearest picture 
