always consider where the product is made.
for example. Clarion/kenwood/pioneer ect are all japanese brands. Designed in japan for little japs who love tinny/treble filled computerised gay music, with a broad range of synthesised and very busy sound.
Japs a particularly good at high range speakers (tweeters and horns)
They are also very good with processors, head units, visual components, and equalisers.
Jap subs naturally aren't gonna be as good as say a USA made sub eg, soundstream/alpine/Boston/Eclipse/mtx/rockford fosgate.
ppl in the US love thier bass, hip hop, pop, blues, jazz.
bass is america's specialty.
So when it comes to SUBS I say go USA made/designed.
USA also has a bigger is better mentality which produces some good amps
If you're after a smooth, rich and refined sound, then head to europe/uk.
Blaupunkt/Bose/morantz/PPI
classical/orchestra/easy listening style music is their specialty.
this means they are best for mid range speakers/splits and mid bass drivers. Amps are good too
Personally, I would choose the soundstream HANDS DOWN.
I try to mix and match brands to get a broad spectrum of sound capability.
I have USA made subs and speakers, allthough I use Boston and eclipse speakers, which despite being made in the USA, are very heavily influenced by Euro design principles.
I am yet to get a head unit, but I'm pretty sure I'll be getting a Blaupunkt or a Nakamachi