They seem to have different pickups, does the S670 have a slightly different trem too? I can't really tell. Obviously I'll go for which ever one has the better equipment and if price is any indication, its the S670, but damn - I want that blue finish!
No significant difference in spec; pickups are both (average) INF models and the trems are both (excellent) ZR models. Go for whichever one you like the look of.
I think the 670 lines are made in Korea and 470 in Indonesia. Not sure, though

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ESP LTD Deluxe Viper-1000 STBC
ESP Edwards E-EX-100STD
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Vox Tonelab ST
Blackstar HT-1R