They both serve different purposes.

Kimono itachi is meant to counter teams based on chakra, especially ones that have innate generation and cant dump it effectively (think edo roshi teams, kakuzu teams with taisho konan- this might backfire hard if you buff kakuzu so he actually 1shots itachi with full chakra!, madara founder teams). In current state of the game you are likely to deny attacks r1 from all earth main teams. In addition he has a nin buff for the column he's in. He dodges mysteries, so his dodge isnt benefit the whole team. He's strong and annoying, but niche pick nonetheless. As for price, about 200cp+ for frag, I think only lucky stars had his frags so far.

Edo itachi on the other hand specializes in taking out of commission 1 of opponent units for 2 rounds. Can dodge chases, so his dodge benefits whole team, as it has a potential to deny high combo chase from stronger units. In addition he shines vs pure nin ninjas (kakuzu standards, sosp standards, all agk teams) effectively halving their dmg for a brief while. And then there's a mirror, so you dont accidentaly cc yourself. He's overall good and can fit into pretty much any team. Top tier support as of now.

Also playing vs kimono itachi without having him is ok. While playing vs edo itachi if you dont have him (and any mirror at all) is annoying as hell. Kimono might be better in certain scenarios, while edo is more flexible overall.