Jackson is all annuity now and has strong ratings (A+ Best) as well as their S&P.
Jackson offers a wider breadth of annuities (specifically variable products) in more states than their more poorly ranked competitors (for the purpose of this discussion).
They also own Curian (who manages separate accounts) and are owned by Prudential PLC (the UK life insurance conglomerate) so I'm not sure if the comparison is accurate.