depends on the size and shape of your head. im not saying i4's are uncomfy, but i've used both and would take my jt's over i4's. my heads big, and they sit tightly along my jawline.
oh, silly me, how wrong i am in thinking all goggles go on the same way and adjust the same way
and a better field of vision
proflexs did, and as far as im aware, still do boast the widest field of vision out of any goggle system.
I think all you're doing is (wrongly or rightly) directing this person into your preferred pair of goggles. without offering any just arguments as to why, or why not, he should choose them.
the bright side of i4's;
extra small profile,
reasonably easy lense change system
downsides (as I found);
did not breath as easy as i'd of liked them to,
were too small on my face, and made me feel ''less'' protected than others have.
Proflex pro's;
amazingly customizable,
breath easy
extremely comfy (comfiest i've ever worn)
downsides;
lense change, whislt not hard, can be awkward (getting the tabs out without hurting your thumbs)
a shot in the lower face plate and you know about it.
Matt;
get along to a tourney, try all the goggles you can (ask around, people are generally nice) find what fits nice on your face and sits comfertably. Dont take the word of a few armchair warriors on the internet. Your goggles are going to be the best/worst investment you make.