ar 234
Given the required target altitude of 8-10k, I think that depends very much on the distance involved. The Arado is not a fast climber and takes room to get to alt.
I did a quick & dirty test - Ozkansas A137 field to A138 town, a distance of about 30 miles, just over one sector - rather typical for MA distances.
P-38L, 100% fuel, 2x1k+rockets (=3560lbs of damage) straight to the enemy base, no WEP usage: 10k reached after 5:20, enemy dar circle after 6:35, over town at 8:37
Arado, 100% fuel, 3x500kg (=3300lbs of damage) straight to the enemy base: Enemy dar circle reached after 05:43 but only at 6k. Leveling off at that point, reached town at 07:44 but still only 6k and not particularly fast.
Alternate Arado mission profile. Staying on the deck after takeoff and intending to zoom climb near the target. Dar circle was entered at 04:42 on the deck but only had reached at 400mph at that point. Zooming up only got the Arado up to about 4k. Much less efficient profile.
So in this scenario, the Arado would have to fly a indirect route to allow reaching the required target altitude. The P-38L is quicker to target and of course much more useful in combat after dropping the ords.
The Arado wins at long distance targets.