The i4s are super small and light, offer great visibility and the lense changes are easy. The downside is they do not breath well at all.
Grillz are also light but a little bulkier. They breath better and I actually like their lens change mechanism more but the extra bulk can be slightly annoying.
Neither breath anywhere near as well as a Proflex/Eflex does.
A friend of mine has Profits and they are super comfy. I'd say they are probably about halfway between i4s and grillz bulk wise (at least that is y impression). I don't know about the lens change mechanism on them or anything like that.
This line is in remembrance of Jared Wilson, friend and paintball teammate who died on 7/27/2005. My Old Feedback +1/-0 | CCM T2 | OLED G6R | Entertaining Offers for either/both
Profits are uber comfy but have the worst breathability of any mask. The i4s are pretty breathable IMO but are small so avoid them if you have large face/head. I would imagine if the E-Flex fits you well the i4 will not.
I would not recommend profits at all really. I have a pair they look awesome and are very comfortable but are terrible to breath out of and you can hear almost next to nothing at all on the field. I would go with the E-flex personally.