I ordered a ZX5 3i to match my last gen set of ZX5/ZX7 combos. I don't use the 3i. I bumped my 4i to 21*.
For me the 3i launches too low to be as useful into par 5s versus a 5 wood/hybrid. But otherwise the club is what you would expect if you have the 4i.
I do wish the loft gapping made more sense on the ZXi Utility compared to Zxi5.