I have never used the Purple Days. I own a Woodeez. Please keep that in mind while reading my post:
In my opinion, there should be no real differences between both vapes. The Woodeez, more or less, is a copy of the PD. The business opportunity for the WDZ arose (as perceived by me) because the PD generated so much demand that the manufacturers could not meet it in a manner convenient to the typical consumer (i.e.- if it can be helped, folks with money and the intent to purchase would rather look at viable alternatives if the original product cannot be procured within a satisfactory amount of time or without a marked inconvenience).
The PD, in turn, is inspired by the Myrtlezap (MZ) or the predecessor of the MZ- the Eterra- I am not so sure about this. However, all 3 vapes (PD, MZ, WDZ) should logically provide similar pros and cons and an overall consistent vaping experience.
If you are willing to wait the few weeks to get the PD, register yourself on the waiting list at vapenow.com.
If you want excellent beautiful beautiful wood and do not mind brass being used in the vape, get the MZ.
If you want a vape you can get your hands on immediately and one that has no brass issues whatsoever then get the WDZ.
The way I see it, all 3 companies provide excellent customer service and stand behind their products.
A side note regarding the brass thing, just so I don't sound unfair to the MZ: I have no issues with brass; brass would never be a purchase deterrent to me. I do not see it as a health hazard the way it has been used in the MZ. Even if I did, I do not vape for health reasons so I really don't pay attention to the possibility of toxins entering my body.