#1 On the Walkera side (Maybe someone else can speak for Blade), you've got the MiniCP and SuperCP. Both are collective pitch and same size. Main difference is that one (MiniCP) supports telemetry so the controller (aka TX) has the voltage and temperature displayed on it. The other (SuperCP) has no telemetry, and the servos are wired directly to the circuitboard, but it's cheaper.
If you're going to get one, you'll have to stock up on a few parts. the parts that broke the most when i was learning were Main motors, main blades, and landing skids. I guarantee you'll break them, so buy spares along with your unit. The motors especially are quite fragile, you can't run them for more than 5 minutes straight or you'll risk them burning out, or melt the plastic frame
Learning wise, be prepared for hours and hours of practice. It'll take you over a month (maybe two) of systematic practice before you can even consider going outside. Sounds too long? Heck, i've heard of people taking as long as three months learning to hover their 450, micros shortened the time it takes to learn not because it's easier, but because we can pile on more flight hours. You can fly 10 times a day with a micro, vs 1-3 times with a 450 (Be sure to stock up on spare motors tho).
#2 Write down you thoughts and post in RC Groups. The newbie section is where you make your own thread and document your experiences
It took me five months to go from a coaxial, to a 450, and the hardest trick i learned in all that time, is learning to hover a micro. Hovering the heli at exactly eye level, walking around it and checking each part for vibrations, and not even needing to think about the controller to keep it still. That took about four months. Of course, i'm also doing fast forward flight by then, but it took that long for one of the absolute basics, Orientation, to really become instinctual.
May seem a long time, but it certainly isn't boring