Road Cycling - old steel?

I have recently been trying out new frames with my ultegra gruppo. I have done a Raleigh R600 aluminum frame and a newer Masi steel semi compact geometry frame. Last year I was riding a Centurion lemans frame that had some flex while the other frames are very stiff . Whereas the Raleigh and the Masi definitley corner better ,the ride quality is not there and I actually go much faster on the Centurion 24 mph average vs. 22mph on the same 6 mile loop with rolling hills. I there an advantage to frame flex ? And if so why does eveyone say it is a problem? Yes it is heavier ,but a good session on the can makes up for that. A friend says that I have a problem with new technology. Maybe so.

I'm not quite sure what, exactly, you are asking. If you like the feel of the bike and feel that it makes you faster, why should my unqualified opinion matter?

There is a school of thought that the energy that is expended to flex the frame is returned when the frame springs back.

Many riders subjectively report that stiffer frames climb better. Personally, I just don't like the derailleur rubbing noise that flexy frames make when I'm working extra hard on uphills.

I guess that I am trying to find a good reason to put this old school frame back in service, even though it is dated ,heavy and ugly, but a sweet ride. It seems the folks I ride with put more value on looks and material than function. A steel lugged clean frame should last for a good long time right? Maybe a new paint job will help.

Actually, according to articles on frame design and dynamics, if your frame doesn't have any designed flex it would be a very unridable frame. This seems to particularly true of the chain stays ability to absorb the side to side alternating stress of your pedal strokes. Without the ability to absorb the stress (especially if your out of the seat) of the side to side and downward pressure your rear tyre would be sliding all over the road.