There is one fundamental distinction, mostly overlooked by new owners and collectors.
I see no mention here.
Here is the real legend.
The original EM Fireball is a Ted Zale design, and the remake is not and was designed by George Christian (EB series, Mystic, Frontier, etc). FB "Classic" has nothing to do with the legend, except for the fact that Mr. Christian was another pupil of Mr. Zale.
Most people do not know this fact.
If a person plays any of the 19 games Ted Zale designed with "zipper flippers" alone including the first game, Bazaar, they learn an appreciation of what he personally provided for innovation and development of pinball design that is used today.
"Mad Dog" cemented the legend with his outstanding artwork, but the theme could have been anything, and it still would have worked.
Artwork is not the critical design feature on pinball games, they are the augment to provide draw but not lasting success.
Dave Christensen did not do the artwork for FBC either, that was the talent of upcomer at the time, a very young Doug Watson.
Ted Zale did not even start designing pinball machines until his 60s at Bally as he worked at Genco beforehand.
Pretty amazing from the standpoint as a pinball designer.
He is one of four game designer "grandfathers" of pinball history (including Ed Krynski, Harry Williams, and Steve Kordek) that taught nearly every single designer in the 80s (including George Christian) and passed their skills into the remaining top modern designers, most of which are in their 60s right now.
People would not have modern pinball without him, yet there are hardly any photos, articles, or references to mark his passing many years ago. It is almost shocking considering his pinball contributions as he designed OVER A HUNDRED GAMES, not considering all the games he assisted in designing and was never given credit.
I not sure where presumption that the EM version is "losing its following" was estimated. Maybe on PinSide? The game continues to outpace the SS remake with the price value of 3 to 1 and continues its offsetting higher every year. More FBC seem to be ending up in landfills, or junked for the MPU-35 boardsets. People are right, the backglasses are trash, as this is after Bally switched to inferior ink screening and heat treatment. Fully restored EM examples can get pretty ridiculously stupid in price (more than that $5-6K), even though other titles he designed such as Op-Pop-Pop, Capersville, 4MBC, Joust, MiniZag, and Nip-It have better gameplay value and remain in some cases completely unknown.
PinSide represents almost none of the EM community at all.
My search of the "right" EM Fireball lasted over 25 years passing over several dozen.
EM games do not use flashers or have electrical circuitry to drive them.
Some do have blinking #455 bayonet bulbs though that run on 6.3-6.5 v, 0.5 amp.
Fireball used a few in the backglass.
There are other various non-descript subtle playfield differences between the two games as well.
The rulesets are different.
The game functionality (not related to EM components) is extremely different.
If chimes are "weak" on an EM, rebuild them, if you want the sound of a gong going off in games, a person can switch out components.
BTW, Fireball does not use chimes, it uses bells, so there is a difference in location, distance, and application.
If a person is still not happy, remove the backbox panel as see how loud the bells can get on a Fireball.
Gameplay skill sets are VASTLY different in order to play either game successfully.
Essentially FB "Classic" sort of looks like, but is not, a Fireball.
It is like comparing a goose to a duck.
It did work well for operators even with the particle board cabinet to attract a slightly older crowd of "remembers" in 1985.
Since the OP is along the East Coast, I recommend Pintastic.
There is special event coming up on Ted Zale.
It might be interesting.