Mike,

When you pay more, you'll get lighter, more vents, one piece molding, this seasons colours.

Having said that, It's your head, how much is it worth to you?

There'a a healthy amount of trickle-down in helmets. Today's £50 helmet is last year's £80 helmet...

The difference in price isn't so much about levels of protection, but other things like levels of ventilation (check vent size and channeling between vents, not just number of vents) weight, fit systems.

I think it is well worth having a well ventilated helmet, as i've found a hot head reduces my co-ordinations and probably reactions too.

I have tried many ACORNS on my head, but I have to say the MET Parabellum is a great lid, with superb ventilation (27 Vents)and terrific value. Also, Met give a crash replacement for £30 quid on this model, should you be unlucky enough to need one. My first Para' was £80, so £30 quid andf no quibble for my replacement was fantastic. You can now get them for about half what I originally paid, so the replacement cost may have even come down.
I think the only difference in paying loads of money is getting the latest kit, and maybe a bit of new technology, or weight saving. The important thing is, finding a lid that suites all your needs,ie, comfort, correct fitting, what use, budget and then colours ect ect. I cannot faught the Met P.
Cheers

I need a new bonce potty. Is it worth spending a small fortune eg close to Hundreds on a Specialized S1, or just enough, for example the Specialized Enduro? Apart from the obvious need to protect the sawdust and fluff in my head, or do the extra quids make any real difference?

To support what Mike says, my new £35 commuting helmet (MET something-or-other) has a better fitting system than my old £100 (Giro E2) one. The E2 looks nicer, though :-)

I have a parra paid 15 quid for it dont ask I worked for halfords and we had to clear it nadf it happened to have a few other offers and staff discount etc fits good but my previous helmet a met crackerjack was just as nice except a bit ough lkike velcro on visor didnt last. Used to seel loads of them which was good as most ppl wnated the cheap lumps of polystyrene