The
Tiger I costs 50 perk points and has 15463 kills and has been killed 3669 times for a K/D ratio of 4.21/1 and 4.37% of the total MA kills.
The
F4U-1C costs 10 perk points and has 5852 kills and has been killed 2315 timesfor a K/D ratio of 2.53/1 and 1.65% of the total MA kills.
The
Me 262 costs 200 perk points and has 2677 kills and has been killed 477 timesfor a K/D ratio of 5.61/1 and 0.76% of the total MA kills.
The
Me 163B costs 50 perk points has 1242 kills and has been killed 434 timesfor a K/D ratio of 2.86/1 and 0.35% of the total MA kills.
The
Tempest costs 70 perk points and has 1168 kills and has been killed 262 timesfor a K/D ratio of 4.46/1 and 0.33% of the total MA kills.
The
F4U-4 costs 50 perk points and has 736 kills and has been killed 241 timesfor a K/D ratio of 3.05/1 and 0.21% of the total MA kills.
The
Ta 152H costs 20 perk points and has 520 kills and has been killed 266 timesfor a K/D ratio of 1.95/1 and 0.15% of the total MA kills.
The
Spitfire Mk XIV costs 60 perk points and has 410 kills and has been killed 276 timesfor a K/D ratio of 1.49/1 and 0.12% of the total MA kills.
The
Ar 234 costs 60 perk points and has 49 kills and has been killed 167 timesfor a K/D ratio of 0.29/1 and 0.01% of the total MA kills.
Look at the kill total on that Tiger I!

That's pretty good for a full priced perk unit.
(Note: The Ar234's unusual nature makes a K/D ratio or kill total irrelevant, though it is very rare)