If I was in your position, and only based on reading the OP, I would choose the Senior Developer position. Before I officially started my career, I jumped between multiple roles, and I've found that the atmosphere of a company makes a huge difference. From what I understand, your current role seems to offer more autonomy, and is less rigid, and so I feel this type of work is more enjoyable (and rewarding) in the long run, even if you'd be missing out some benefits and career growth.
Now, if pay and benefits are a bigger deal to you, it might be wiser to choose the bank position, but I know I personally wouldn't enjoy a role like that. Whatever you choose, make sure the value the impact of whether or not you can see yourself enjoying it on a daily basis. I've worked jobs in the past where I would dread going in every day...and I really don't wish that on anyone. It really is unbelievably draining.
NNID: Zephyr25 / PSN: Zephyr--25 / Switch: SW-4450-3680-7334
