YOshi,

of all the arranger I have played and owned, the Roland G-70 and the Korg PA2X Pro have to me the best key feel. The difference is that the Korg as a heavier action (almost piano-like) so, if you plan to play a lot of organ sounds, the keys could hurt your fingers if you do a lot of smears.
Speaking of synth-like action, the Tyros 2 has an excellent keyfeel.
I have never played a PA-800, so cannot comment on this.
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Korg Kronos 61 and PA3X-Pro76, Roland G-70, BK7-m and Integra 7, Casio PX-5S, Fender Stratocaster with Fralin pickups, Fender Stratocaster with Kinman pickups, vintage Gibson SG standard.