It used to be that a collector would pick up just about anything at a good price, fix and then re-sell or trade it in order to go "up the ladder" to more desirable games. The collectors that desire EMs however dwindles every year and so does the demand and selling price. ZSO what brad808 says in terms of saving money towards something you'd rather have is very good advice IMHO (take it from one who has a few "dead woods" sitting in their basement).
That being said, you've stated a different purpose which is admirable and an EM will always find a welcome home in a larger collection as it helps preserve the history (and has an entirely different style of play, sounds, rhythm etc.). I find that my "new to pinball" guest almost always gravitate towards EMs as a starting point AND EMs are especially fun to play with others of similar skill (or others of better skill on newer games - they are almost always challenged).
I've always found "spinner" game EMs to be fun (put a tiny bit of Super Lube in the wire loop for "wild" spins). I've never tried this particular one. Read the IPBD reviews, for what they're worth they usually come from EM fans, but in the end $300 is a small price to pay to ride (and I'll bet others here - maybe even I - would buy it off you for same if you didn't like it).