I hate mbtc. Still haven't figured out what people mean when they use that unit. I wish they would stick to btc. I'm used to the decimal point and the zeroes. It's actually quite easy. You just count the number of zeroes right after the dot to get some semblance of the value.
The problem is that you have to count, with mBtc you get some semblance of the value faster.
You only have to count up to 3 zeroes. Take the default transaction fee for example. It's 0.0001. So anything with more than 3 zeroes is just too small to care about.