open mould & expensive equivalent

People were saying on here that one of Merlin's in-house offerings was actually a Ridley, but frankly if you look closely its really not the same at all, even in looks. Close, but not the same.

I don't know of one, but in general only the big bike manufacturers or expensive niche brands have their own moulds and designs. Also retailers who have suddenly started making their own brand of bike e.g. Wiggle, I believe use open moulds.

Even then, many big companies with a propietary design still outsource the actual production to other companies (e.g. Giant make for some big brands).

Yes the concern around open mould frames  is really only related to those that are copies and made, for example, by  foreign companies, often in China, who might not provide a warranty or customer support in the event of a problem, or who are unclear about the provenance.  

The same applies to wheels.

Companies who stand by their products and particualry those who have full control over all stages of the manufacture are likely producing a better product and customer experience. Whether they use an open mould or not doesn't really matter, other than perhaps you're not getting the very latest design.

The first thing to emphasise is that even if two bikes came out of the same mould, if doesn't mean they're the same bike.  Even if (and it's a big if) the material is the same quality (Toray T800 or whatever), the skill of the actual worker who does the frame layup matters.  Think of a pile of food - I can take the same pile of food and the same pans, but the meal that Gordon Ramsay or another Michelin-starred chef would make will be much better than what I'd make.  Just because it's the same shape doesn't mean the clone has the same layup and therefore the same characteristics.

Which is not to say that all clones, or even all 'no-name' frames (Hongfu etc) are rubbish... but some might be, and you pays your money and takes your choice.

Also, not all bikes are made from one original mould - you can find designs where the front triangle is borrowed from one frame and the rear from another, which makes spotting them a bit more fun.

The De Rosa R838 was widely cloned a little while ago, I forget exactly which other bikes were the same shape though.