Hi, I really need some guidance here. I'm African-american and Puerto rican, and I have 3C hair/4A hair. It's really thick, curly, and coarse after washing it, and very hard to straighten. With the straightener that I have now, it takes me 3 to 4 days to get my hair to stay straight without getting very puffy again

Once those 3 or 4 days have passed though, I keep my hair in loose curls and it it stays very manageable until I wash it again.
I REALLY need a flat iron that will help me maintain my hair better. I'm hoping for one that will leave my hair silky, pin straight, and one that will hopefully have ceramic plates.
I once went to a salon and they made my hair similar to that of someone with naturally silky, fine hair. I'm hoping for a flat iron that can easily give me those results again after I blow drow my hair.
I've looked into many different brands, and have heard great things about the FHI, GHD, and Profashion (all professional flat irons). I just DON'T want the CHI.
PLEASE HELP!!!?