The Super Flower Leadex VII XG 1000W wins in 8 out of 9 comparable specs. Its biggest advantage is Efficiency (150% better).
500 BQ wins in 1 spec (MSRP: 75% better).
Recommendation
Choose Leadex VII XG 1000W if you want the best overall performance — especially efficiency.
Choose 500 BQ if msrp matters more to you.