This is really an apples to oranges kind of comparison. Two totally different animals.
The PD is great for conservation, durability and fixed temp but really is more of an 'at home' type vape.
The Iolite has fixed temp but not as good for conservation. Has more working parts to fail as well but I've had good luck with mine. The Iolite to me is a portable vape while the PD is daily driver at home.
Odor control depends mostly on your exhale for the PD. The Iolite does emit smell even when you're not drawing.
If you're on the go a lot and looking for a good portable the Iolite is a candidate and I would highly suggest looking at the Magic Flight Launch Box for portability as well. Very durable, lifetime warranty and does not emit a smell unless you blow a cloud out. It is also VERY conservative compared to the Iolite.
If you want a VERY conservative home vape I cannot say enough good about the PD. An awesome vape, very well built and always ready
Good luck!