Ultimate Perk combo

After doing my placements and testing out all her perks, i've found the perk combo that I like the best and that really made an impact during my games.

Angelic Recovery + Flash Heal for optimal performance

Angelic Recovery comes in handy when you're being focused, but your ally is full hp. Also, you don't have to have the healing beam on them, you can continue to damage boost and the perk will take effect. Winged Reach doesn't do much since during team fight you should be close enough to your team to where you won't need the extra range.

Flash Heal because one of the things that has held Mercy back from being a more viable pick is her lack of burst healing. During a team fight sometimes no one dies, but your team could use the extra healing, or somebody does die but you can't rez them because you'll die too. The burst healing has already come in clutch so many times for me while doing my placements it'll definitely be my number one pick. Chain Boost sounds good on paper, but most of the time you're with only one of your dps. Not to mention that during Valk you have chain beams.