No worries mate, here to help lol. I forgot to mention with any internal BEC on an ESC there's the issue of heat.
The reason why Linear BECs are terrible is because in order to transform the high voltage of your battery pack (for example a 3s LiPo is 11.1v) down to 4.8-6v for your receiver, the Linear BEC just bleeds off the extra energy as heat. Obviuosly, the hotter the BEC and ESC gets, the less the power output becomes everything becomes less effiecient.
All a switching BEC does is switch on and off really fast, so the voltage going to the ESC is 6v, down from whatever. They have the same heat problem, but MUCH less than a linear BEC.
That's why I always use a external Switching BEC. Here are a few:
Dimension Engineering ParkBEC - Good for 5v output and 6v-33.6v input
I don't have any of these because the output is only 5v
Dimension Engineering SportsBEC - 5/6v selectable output and 9v-33.6v input. These are awesome little BECs, I got a couple
Castle Creations BEC - Programmable output 4.8v-9v, max 25v input (6s LiPo). These things are tiny, awesome, and programming the output voltage by the computer software is so cool. You have to buy a castle link cable seperately however. I got 2 of these, which I use in my brushless conversion cars.
Just be aware with the CC BEC, when it fails, in most cases it fails OPEN. That means when it dies, it doesn't close the circut, it opens it, meaning that FULL voltage from the battery pack goes straight through to your electronics. So anything much over 2s LiPo would mean death to your electronics.
All that said, I abuse the 2 I have and have had no problems so far (fingers crossed).
If you want, you can swing me some rep points (click the button that looks like a set of scales under my name to the left <---)