Plenty of vector work is done in PS. I only know of people using Illy and PaintTool SAI as alternatives. But then again, it's not my style, so don't take my word for it.
Check out the pentool tutorial I posted in your first thread.
You have to keep shadow's in mind as well. Maybe "flail out" the tentacles and add more detail.. not too much seeing as this is vector but some more time with them should help the image out a lot. With the tentacles hanging down so simply makes the image loose dimensionality (Pretty sure i am using the correct term), it makes the character less "real", so to speak.
Maybe work with posing and giving your character consistent highlights and shadow's from your light-source, wherever that may be.