Do you need healing? Or do you want to deal dmg and punish your opponent. I also believe that using the bat would require better reaction and timing than using magnet since bat comes out slower than magnet and you have to time the bat to reflect the projectile.
Lets use Samus as an example, lets's say Ness and Samus are both at 100% and Samus shoots a fully charged shot.
You have two options
a) Use the PSI Magnet and heal yourself like 20% or whatever it is.
or
b) Believe in your reaction and timing and punish and kill the Samus with bat reflect.
(The closer the range Samus fire her charge shot, the harder for you to react and absorb or reflect it, but keep in mind if you are able to reflect the charge shot, it will be harder for the samus to react to it too.)
If we use the same example, but Ness is at 100% and the Samus is like at 20%, I would just heal since, a reflected charges shot wouldn't kill the Samus, but the choice is up to you.