First, You asked about french enameled cast iron. I've known people who owned the cookware you are talking about. Their universal opinion was absolutely do not buy it. I knew one housewife who did like hers but she wasn't the best cook I've ever known. She cooked more for show than for real, if you know what I mean. Enamel is an expensive solution to a non-existent problem. People don't want all "the work" of cast iron so Le Crueset puts enamel over it. Viola, no more seasoning, just wash up in the dishwasher, etc. Problem solved! Enamel chips and cracks. You chip the cook surface of the pan and it's effectively ruined. It's also horribly expensive. If you want a no muss, no fuss pan then just use your stainless steel pans you have now. They are fantastic. If you want cast, buy a Lodge at the hardware store. Is it bad? Well compared to Granny's Wagner, sure it is. Can you cook just fine with it? Yes. It just takes more work.
Second, Texguy is spot on. I appreciate all the people who love cast iron, as I do. However, all the work that goes into these things that some people do, it's like buying another pet. I've used cast iron for many years. I've adopted the Alton Brown method which Texguy states, basically.
"Cover it in oil (any kind is fine) and bake it in the oven upside down at over 400* for over an hour. Then let it cool until you can touch it. Yes it will smoke up the house."
However, I use 350, and not "any oil." I use lard preferably. As for smoking on the fat. Not sure where that's coming from. You are cooking on the fat, not burning it on. You burn fat/seasoning/rust OFF and cook seasoning ON. So just bake some fat on, below it's smoke point. I know Jack's guest said the oven thing was silly but it sure works well for me and has for 20 years. It just kick starts the seasoning. After seasoning you are 85% of the way there. It's not "non-stick" but it's usable. Then just cook high fat items like bacon for a while, or put a bit more butter in with your eggs for a while. Before long you'll realize that stuff just isn't sticking. My aha moment was when I was going to season someone else's pan and put it beside mine. I had no idea just how black mine had gotten. Really amazing difference side by side.
Cleaning cast isn't harder, it's just different.
How to clean
http://www.youtube.com/watch?v=8z3c3_CB-2sIf you don't own another cast iron pan, own it for this one recipe. Haven't touched a grill in MANY years.
steak cooking
http://www.youtube.com/watch?v=3yX1Q3x9Cs4Yeah first of all, if I smoke up the apartment, the smoke alarms will go off and that's not a good option. Doing it 20 times would take me forever so I need to use the shortcut version. I cook bacon maybe 1-3 times per week so if I just do that, I can probably get the surface done in about 2-3 months maybe.
More like a week and a half.