I’m a Pixelmator guy but tempted to give Acorn a try - it’s 15 bucks right now on the MAS, down from 50.
https://itunes.apple.com/us/app/acorn-4-image-editor-for-humans/id634108295?mt=12
I have been using iDraw. Is Acorn better than iDraw?
Mainly using Pixelmator and Sketch, but for this price i think i’ll try it 
Thanks for the info @Gavin Smith
Shameless plug. PaintDS is about to be re-released with a ton of bug fixes, upgraded to COCOA, and its $9.95 
Not as fancy as Pixelmator, more a beefed up clone of MSPaint
I also use Pixelmator, great program.
Another one to take a look at is Gimp (FREE), they no longer use X11.
Will take a look at Acorn.
Thanks for info.
The problem with Acorn is that it is not possible to modify (resize, free transform, etc.) several layers at once, or even more than one vector shape at a time. For me it makes the app almost not usable, but it might depend on the preferred style of work, I guess.
A free demo is available at http://www.flyingmeat.com/acorn/, so you may check it before buying.
Just tried Acorn in the hope it has good vector support, but it seems to be very basic. I hope Pixelmator can some day import/export vector files.
Pixelmator has a hidden full fletched Vector mode: Command-Shift-V
BTW personally I don’t like Acorn.