These units have a magnificent perfomance even at vet0. And yes, OKW are more expensive due to its better perfomance and possibility to reach vet5.
Puma, Jagdpanzer, Stuka, Panther, Sturmpio, etc, are in much better place at vet0 than their allied counterparts. Only volks are more or less equal to allied units, for that their price is cheaper, althought their vet is awesome and they scale very well due to its panzerschreck upgrade.
Mostly yes, bud Panther for its cost? Not really.. And as i stated earlier, Vet 5 is almost impossible to reach with most OKW units