Complex sentence: Jarret Records released albums by Anything Box but vanished within a couple of years, while longer lived has been Synthphony, who initially released single artist albums but recently have released mostly remix collections.
Split into simpler sentences: Jarret Records released albums by Anything Box but vanished within a couple of years. Synthphony on the orher hand has been longer lived and initially released single artist albums but have recently released mostly remix collections.