I would look into the pricing and choice of lenses. YES L glass is great but only if you have the money to buy it. Prices in the US may differ greatly to other places in the world and so will availability.
style="BACKGROUND-COLOR: #000000"If you are coming from z7590 you are bound to have access to some nice zoom power.(i came from a z740 and 18-55mm just wasn't enough for me )I would opt for the a100 in case you want to buya cheap x-300mm and want todo handheld at 300mm the SSS would help you there. ( the budget solution )