I've seen some posts about the the mouthpiece and thought there needed to be some clarification. Many folks including myself feel that the Penelope mouthpiece is the most comfortable. If the Ithaka mouthpiece is made like the iAttys then it will not be like Penelope's or Odys straight one but more like a traditional contoured mouthpiece.
I have an iAtty and while it has the best contoured tip I've ever tried and is very comfortable, I prefer the straight tip. There are some good quality straight tips out there comparable to Penelope's so if that's what you prefer, you will not need to buy the optional GG mouthpiece, only a straight tip.
Wait!! What??! Now I'm confused. Hoping this is not correct. I know Siam and Caravela sell a straight tip which give things more of a GG look but not integrated like the real deal. Can someone confirm this?