I started with the Hubsan 107L to learn to fly, have been having a blast flying it and have gotten very good at flying. I moved up to a 250 racing quad to begin learning about FPV, got a Lilliput system and also the Skyzone goggles. My skills I acquired flying the Hubsan micro quad paid off, I handled the 250 without any problems, just smooth flying. And the learning curve was then mostly getting used to using FPV and the new to me Futaba devo 7 radio that came with the 250. Like you, I took an interest in the F550 Flamewheel that HeliPal had to offer and bought it. I added a second FPV camera (the 700 like what was on my 250) so now I can fly FPV and also fly using my Go Pro, is a win-win with both.
I have plenty of experience building some small quads for my grandkids, plenty of experience repairing the Hubsans, so now I have decided to go ahead and build a few things from the ground up. I really like the 550 platform, but I wanted a little more power and slightly more size, so I am currently working on a 550 frame/board setup with the longer aluminum arms so I can add the larger motors/props without getting too large in the overall size. If you need more real estate to mount things, you can always add a 3rd board on top of the other two, or add below with things attached to lengthened camera arms for a gimbal and dual battery setup. That's the nice thing about the 550's, you have some room for growth without building another multirotor from the ground up, they are more expandable without going into all the total costs of a new setup.
Whatever you decide to do as far as RTF or ARF, it can/will be fun and you will grow with whatever direction you decide to take. I think the best part is that while you are doing things and learning you are having fun.
CD