I, personally, recommend getting a VV battery to start. It gives you control over the heat of your vape. Some of my juices taste better at 3.5v, some like a little more heat to wick properly.
The Aspire Nautilus is a very popular model. I love my Aspire ET-S, and the coils, so I'm sure the Nautilus would be a great upgrade. However, the coils are somewhat expensive, and sell out frequently. Have you considered the Kangertech GeniTank? It's a similar size, cheaper, still offers adjustable airflow and large juice capacity, plus the coils are cheaper to replace. You may even be able to rebuild your coils, to get your feet wet with a rebuildable. Plus, you'll still get a glass tank. That's something to think about. Plastic tanks will reduce your juice selection. Some juices are known to crack plastic tanks.
Good luck with whatever you choose for your starter kit.
Happy vaping!