Of the three I would go for the Cobra but that's partly a mixture of aesthetics and what I have heard about the three of them.
To be honest, you need to try them first to see which you feel most comfortable with. I've done this in the past and walked away with a totally different set to what I thought I was going to buy.
they are all very good irons, best to try them out if you can see waht feels best, and as eveyeon ssays try to get custom fitted if you dont, you will want to down the line as you get better
I bought mizuno mx 19s from AG wich have just been reduced to £249. They are good excellently manufactured forgiving irons. Jury is still out as to whether they suit me personally - I'm goin out today with my old pro combos for a practice roud to do a comparison - typical me - too bloody impetuous!
I got the MX-19's from DG for £225 (3 - pw) and I'm now starting to love them! I went through a period of time where I thought I'd blown my money on clubs that didn't work for me but all they were doing was highlighting the (many!) problems with my swing!
BB
(yes I know they're game improvers - my swing was rubbish!)