I like my i3 Pros and Proflex about equally.
Pros: Comfortable (preference), dual paned thermal lenses, small profile, semi-bouncy, decent breathability, nice soft ears
Cons: Lens removal
Pros: Customizable, lightweight, breathable, comfortable (again personal preference), dual paned thermal lenses, very flexible (bounces)
Cons: Lens removal (not as bad as the i3 Pros), the soft ears are kinda lame compared to the i3 Pros (IMO)
Both are great masks, I'm leaning towards the i3 Pros as of right now due to it fitting on my face a bit better. Most people are scared away from the i3 Pros because of lens removal and stuff. Yes, it does suck, but I've only needed to remove the lenses once (though I've done it more than ten times). Go try them on and see what you think.