Both are good brands. Blaupunkt, being a German brand, is used by German cars like BMW and Mercedes. If the Blaupunkt is original, it will sound good. The ones i've heard on the BMW 5-series (525i) and MB E-Class (E320) are very good.

JBL is also good. Sounds kind of bright (high treble) but delivers superb sound clarity and bass.

Both are good. Just watch out for fakes. Blaupunkt, if original, is very very expensive.