One thing about it if you keep your Steem tokens you'll have ownership rights to both the Steem chain & the Tron chain tokens.
Like ETH & ETC. I would expect most the value to accrue to the Tron Steem token considering but it's going to be in the details of what Sun plans to do with Steem.
RE: “Steemit joining the Tron Ecosystem” - What it means