Congrats on learning to hover with that mcpx. The micro size CP helis are tough to learn on from scratch. Not many succeed. Especially self-taught.
When you step up to a large heli you'll be amazed at the power and also how stable it is by comparison. And, yes, you are ready for a larger heli if you're hovering and perhaps moving a micro in a smallish space without issue. At about a similar comfort level you're describing with the micro size CP heli, I jumped from a nano cpx to a Blade 550X. It was fantastic and seriously hooked me on the hobby. As such, I think the 550X is a great intro to the larger size helis (especially if you can find a deal on a used one). 450 size T-Rex is another great option. Personally I'd steer away from the 130, 150, 250, 300, and 360 size stuff for your next one. They are more trouble to work on, tend to have flight behaviors that can be difficult to deal with when you're still learning, and may very well turn you off of the hobby and prevent you from taking the plunge to a proper "larger" size heli.
On radios: The new DX6 looks like a fantastic radio, with it out the DX6i is only worth it if you are looking to buy cheap now and upgrade later. It has a lot of the features of the DX9, but at a budget price and enough channels to satisfy most needs until you get an itch for scale helis with retracts, lights and the like. With the recent release of DX6 and DX9 there are likely a lot of DX7s's and DX8's out on the used market, seriously consider them too. You can always resell later if you decide you want to upgrade and not end up taking a big hit since you're buying used to begin with.