Alvarex, Khabib, RDA, Ferguson, Diaz, Cerrone, Poirier, Dariush, Brooks, Barboza, Iaquinta to name some UFC lightweights off the top of my head
Chandler, Saad Awad, Pitricio Pitbull, Derek Campos, Ryan Couture, Dave Jansen, Melvin Guillard (kinda), Benson Henderson, Josh Thompson to name some Bellator lightweights.
Yes some of these guys are more accomplished in the opposite org but now fight for the other.
You decide. LW and FW have always been strong divisions for Bellator. But I think the UFC's is way stronger. Plus all the lesser name guys. UFC also has more LWs.