The "geared spinner" refers to the way the original hardware was built- the spinner knob turned a series of gears that then turned the encoder wheel, instead of just spinning the encoder wheel directly. This had two effects: The encoder wheel spun really, really fast with just a small turn on the knob, which allowed for very precise control in the game. The other effect was that the "feel" was different from a standard spinner; there was some resistance to turning the knob, and it wouldn't keep spinning if you let go.
Both the SpinTrak and the TT2 have very high resolution, which means they are capable of reproducing the high level of precision the original did. They're not identical in this regard, but they're both probably good enough for all but the most fanatical players. None of the other spinners on the market come close in terms of resolution, although many people report the game still plays well enough for them with different spinners.
If you get the TT2, and the TokenTop knob, there is a resistance device built into that knob that creates spin resistance to emulate the original Arkanoid spinner as well. No other spinner currently available does anything in this department. There's a review available at
www.retroblast.com.
The Apache is still the only offering with push/pull, if you care about Discs Of Tron, Zwackery, or Forgotten Worlds.