For PS CC and possibly Illustrator CC later, is Wacom Intuos Pen and Touch sufficient in size and capabilities for IMAC 27in with Retina and OS X Yosemite

Hello,
For  PS CC and possibly Illustrator CC later, is Wacom Intros Pro Pen and Touch Medium size sufficient in size and capabilities for IMAC 27in with Retina and OS X Yosemite . . . I have no experience with tablets and just starting with Photoshop CC . . .
I was also debating whether to get Wacom Centiq 13HD that has larger active screen but have read the screen does not have a good resolution  compared to the IMAC 27 in Retina screen.  I am an amateur not a designer but would gradually use it for a bit of drawing once comfortable with Photoshop.

Pls advise,   many thanks