Quoted from Crile1:

Go with an LE. There are 3 versions available, LE, Smaug LE, and Black Arrow. Smaug's came out first, so are older. Make sure if you get one it has all the fixes. LE and Black arrow LE have all the newer fixes because they came out later. Only other differences are aesthetics. Different decals, different armor (gold, copper, and black) Smaug has gold dragon instead of red, and Black arrow has black flipper buttons and a black ball to react with the Newton ball. Both black arrow and Smaug have a different animation sequence as part of the attract mode. I bought an LE because I liked the side art the best, prefer the copper tone powder coated armor (didn't like the gold and Black is kinda plain) and prefer the red dragon. Didn't care for the black ball (hard to see). Love mine and have never had a problem other than replaced a broken spring and some switch adjustments. Not bad for over 1,000 games played. I have mine at 7.0 degrees and it plays fast. Hope this helps. Love mine and at the current used prices would jump on an LE (of your choice) especially since there is prediction of a big code update coming this summer. Don't do a standard. LE gets you the barrel pops,invisiglass (yes, it's great) and shaker. Buy the ring button mod from Flip n Out pinball, worth it.

Quoted from Rdoyle1978:

Smaug; best armor, extra video stuff - game kicks ass

Quoted from Rdoyle1978:

Not all of them - the left wireform was slightly redesigned - some games needed it, some didn't (mine didn't). The right wireform almost ALWAYS needs to be tweaked a bit but was not redesigned (takes about 3 seconds to adjust if needed to avoid outlane drains off the wireform). The beast mechs were upgraded during the initial run of Smaug SE, but as was pointed out above, are MUST-haves. And a huge pain to install. There's a white plastic insert/spacer that is added. that's the main change - get one with those, you will never want to install those damn things.
Jack made a video about the upgrades, but the main thing is those mechs - it keeps balls from getting trapped under the mech, which is very important to avoid. » YouTube video
so anyway, you have to check the specific game you're buying. most should have it by now -