The Magnetek 950 is a decent charger - probably the only good one that Magnetek made. It's still a two stage, though, so the Progressive with Charge Wizard (making it a three stage) will be better. Whether it is $290+ better only you can decide. Also, the 9260 is a 60A vs 50A on the Magnetek and that extra amperage will help charge your new and much larger battery bank a bit faster.
If I were going to spend the money to change chargers, I would probably go for a larger one., e.g. the 80A model (pd9280). It's only about $20 more.