On its face, Cleveland wins this trade because they added IT, Crowder and the 2018 Nets pick and only gave up Kyrie (who already made it clear he wanted out). But there's a risk that this blows up in Cleveland's face.
Bron is pretty much gone after this season. IT will also be a free agent demanding max contract money. At best, the Cavs find a way to keep both (highly improbable), add some players (Melo/Wade),and try to compete with Golden State for the next few years

. At worst (and more likely), Bron and IT bounce after next season and Cleveland's stuck Crowder, Thompson, Love and trash.
Celtics understandably moved on from IT. He's in a contract year and has made it known that he wants the Brinks truck. But Boston cannot commit max-contract money to a soon-to-be 30 year old 5'9" PG who can't play D. At least with Kyrie, Boston gets a much younger PG that has championship experience and is as deadly a finisher as IT. Although he's not a great defender himself, it'll be easier to hide Kyrie on defense than Isaiah. And Kyrie's under contract for another 3 years.
Giving up Crowder is going to hurt Boston but now there are guaranteed minutes for Brown and Tatum to develop into contributors. And the Morris pickup is going to help fill the void left by Crowder. Cleveland's happy.
The loss of the Nets pick may be what fukks over Boston. The 2018 Nets pick isn't guaranteed to be a top 5. The Nets are by no means a playoff team but I don't think they'll be any worse than last season, especially with the addition of D'Angelo. There may be worse teams in the conference and that's before we start talking about the worst in the West. But even still, the Nets may very well be trash again.
Short term: Cleveland won. Long term: Boston won.