What's a good flat iron?

I have naturally curly/wavy hair, and I'm fine with my hair but I like wearing it straight sometimes but the flatiron I currently have doesn't work on my hair. Now I have the CHI and everybody says that the CHI works perfectly for them and all that stuff and I keep telling them it doesn't work on me. My old hairdresser used the CHI and my hair was never straight it was like puffy. My new hairdresser does not use the CHI and when she does my hair it looks great, when a friend did my hair she didn't use the CHI, AGAIN my hair was straight. So bascially I need a really hot flat iron to do my hair, any suggestions??