Trust us...
Pro-motion is THE tool for low color pixel work...
Photoshop is THE tool for high end pixel work...
Doing low color work in Phostoshop is just wrong. - likewise - doing high color work in Promotion is WRONG (neigh impossible as it doesn't support it) - even if Jan (zimmerman) does get around to incorporating high bit ratios into promotion I doubt it'll better the potential of P'shop.
Based on DPaint - (THE tool of the 80's/90's) - speak to ANY old skool pixel artist like myself and they will sing it's praises - I jumped onto the Promotion Band wagon back in late '97/early '98 - and every iteration since then it's improved... it's the tool that's propped up the GBA art creation industry in the UK/Europe/US since it was released...
As far as the other pixel tools that you guys seem to like...
Paint Shop Pro is lame.
Graphics Gale has it's plus points but isn't a patch on Promotion
And MS PAINT!!! JEEZ!!! I can't begin to say how utterly dogshit that is as a pixel package...
Dunno about Idraw - never seen it... but I doubt it's as good as you say.
Ta

That's all you need to know...