Imo the Pa50 doesn't sound tiny or thin at all.
Even out of the box (no tweaking), both Pa50SD /microArranger arrangers
sound "fuller" (deeper body) than the Yam PSR series models. Again, JMO. Scott

I believe the choice of arranger brand may be best determined by the genre and style of music you do most, and to what audience you are playing to. For an older senior audience perhaps a Yamaha PSR may be more ideally suited, and for more contemporary pop and rock music venues, the Korg arranger a better choice.