Regarding target users for specific price ranges, I do agree that high budget arrangers are not bought only by professionals, but here majority of the users that do buy it are professionals, because this price range is way out of the home/amateur users. Also, here many professionals use middle budget arrangers.
You have to take into account that high end arrangers like Tyros2, Roland G-70 and Korg Pa-2xPro, here costs around 3.000 EUR (4.500 USD) and the average monthly salary is 620 EUR (900 USD) so it would not be a wise decision to buy something just for entertainment and work almost half year to pay it off. Therefore, only professionals (who earn money by performing on arrangers) can afford to buy them. Situation over there might be different, but here, that's the case.
I'm considering to buy Korg Pa-500 (should be available on the market within a month or so) primarily because it has lots of features and the price is not far from European (950 EUR or 1400 USD). Rolands are to hard to find (just one dealer), and the prices are high (1700 USD for E-50, 2100 USD for E-60[my favourite]). Yamahas are easier to find but also too expensive (PSR S-900 for 2800 USD, PSR S-700 for 2000 USD). I would like to buy 76-keys arranger because I don't want to play it in arranger mode only, but also in piano mode.
My primary reasons to buy (or not to buy) an arranger, beside the price, is sound quality and features, not the number of keys, but if I could buy 76-keys keyboard with same features (and not to pricey) as 61-keys keyboard, I would prefere the 76-keys.
[This message has been edited by kalimero (edited 04-04-2008).]