He makes an excellent point that you must consider. Even with an advantage, and presuming you play flawlessly and with a proper bet size/spread, the swings can be murderous. I don't know too many people with the fortitude to do it as a profession, regardless of their skill level. I admire Francis and the other pro posters, but that lifestyle isn't right for me.
For me, I have always viewed counting as a way to supplement my income - like a second job - so I call myself a "semi-pro". My bankroll is set at 100K. If I get crushed, I may back down on bet size until I bring it back up to 100K.
If I have a big win, I treat myself to something. Once this was a Mercedes E320 after a +$40,000 trip. A Rolex for my wife was another treat, and insured that I could go back many more times! :). I also used to make lump sum payments on my mortgage with winnings. Whatever I rewarded myself with never took the BR below 100K.
That keeps it fun, and I get to keep my day job, which is pretty cool.
Remember "Gambling is a hard way to make an easy living."
This is what works for me.