Personnaly I bought 4 cells 163ah in november last year and I'm verry happy of them.
I'm in France, and I get thoses LifePo4 cells in 10 days, european stock, all right, grade A.
So now I just purchased another cells, 304ah now, from the same shop in Aliexpress :
BLS Official Store
Discover the wide range of products from AliExpress Top Seller BLS Official Store. Enjoy ✓Free Shipping Worldwide! ✓Limited Time Sale ✓Easy Return.
a.aliexpress.com
They already have USA warehouse for Quick delivery
I Always use PayPal to be protected.
Another shop with goods review but not tested is
liitokala Official Store
Discover the wide range of products from AliExpress Top Seller liitokala Official Store. Enjoy ✓Free Shipping Worldwide! ✓Limited Time Sale ✓Easy Return.
a.aliexpress.com