Electronics refers to servos, gyro, motor, esc, receiver - everything electronic

The servos are the main thing that people seem to complain about, but I'm sure you can do with a better gyro which will make it easier to fly, as well as better motor and ESC which may or may not be necessary.

The cost can vary quite a bit depending on what you get. I don't think it's worth getting a blade 400 just to switch everything out though. I think it will end up costing more in the end.

The nice thing about Eflite is that it's assembled and they have good instructions compared to a lot of the other brands. Align has pretty good instructions also. The clones aren't going to have very good instructions making it more difficult for a first timer but you can find lots of info on the web. The principals are nearly identical for all the eCCPM electric helis.

I really have mixed feelings about eflite. As I said, my first heli was a blade CP. I think they're a good company that make some fun helis. The coaxial and fixed pitch helis are fun and good quality for what they are. But for CP, I feel like they're more of a "get your feet wet" kind of deal, if you stick with it before long you're going to want something better. So if you're sure you're going to continue in the hobby, in the long run it will be more economical to get something better up front and spend the time learning how to assemble, tune and fix it. If you're not sure and just want to "play around" or try it out before jumping in, the the B400 is an easy affordable way to try it out. That's how I look at it.