The Cotillion is a good sounding Lowrey, one of the best ones before they 'lost the plot' with the awful Genius things.
No leslie for the flutes but a very good Vibratrem electronic tremolo, that keeps the flute sound nice and smooth like it should. Strings and Brass are typical Lowrey - typical analogue, and again, are nice and warm. It has a Choir on the lower manual that cycles through various vocal soundsas keys are struck. This can be quite effective. You also get the Harmony Plus feature, Lowrey's first advanced version of AOC.
Downsides? Rhythm box is a bit iffy-sounding and things like Piano are nothing like what you'd get even on a cheap keyboard today, but that's about it.
I'm not sure what $500NZ is in 'real money' ie £ sterling, and I don't know what the NZ market is like, but don't pay too much for any organ of this era. If it has any electronic problems, factor the potential repair costs into what you're prepared to pay.