I'm choosing the Chain Boost perk over Flash Heal 99% of the time

Chain Boost just feels better and more applicable most of the time. Being able to boost both DPS at once, boost a DPS + Tank, or boosting DPS + Hybrid Support just feels too good. Plus getting increased ult charge for both of them allows you to snowball ults faster.

Also prefer Chain Boost because I'm hoping they remove Flash Heal and give that as a regular ability with a separate cooldown in the future instead of tying it to Res.