I agree with Shanty's comments and having owned a very well built 42ft steely, I feel I can comment on the matter.
If you are a fussy bugger like me - don't get one, either that or paint the hull brown!
Constant touching up of those small rust spots that if not jumped on, not only look crap and create stains, but get worse.
I would say most of the problems that occur with steel boats is the appearance - not so much structural (if you start with a good one) - although appearance may not be an issue for some.
Displacement: My yacht weighed 14 tonnes. She absolutely loved anything 15 knots +, but struggled in the light stuff.
Fairing: Fully faired hull, the fairing can fall off if it is damaged and water gets in behind it. Of course, not fairing a hull negates this, but generally looks inferior - "starved dog look".
Bilges: Steelys usually rust from the inside out - keep the bilges dry!!
On the flipside;
Strength: I've been in some heavy seas and the stiffness in a steel hull is a real confidence booster. Slamming down the other side of breaking waves and the hull feeling as stiff as a well built 14ft tinny.
Encapsulated keels: I just like the idea for strength as opposed to bolt ons.
Lightning: Much has been documented on it's better to be on a steely or fibreglass yacht. I'm going with steel hull on this one.
Anyhow, these views are just my own, plenty of people will probably tell you otherwise!