Sam I believe that carbon fibre tanks are the best, even though they're be more expensive the carbon fibre tanks are usually more efficient and of course are lighter... Gain some more advice and do some research then decide fr yourself
Those points are valid, but seperately.
A number of years ago I found on this and many forums that I would often be shouted down for promoting 3000psi cylinders rather than fibres when new players were asking about what to get.
The comment was always that the fibre would be bought soon after so the money spent on a 3000psi was always wasted. Possibly people set in their way, possibly that they didn't want to be the one speaking differently.
It can be a waste of a starters budget - there is so much to take money from the beginner
The general point of view has changed and players appear more informed.
A fibre cylinder is never 'more efficient' - by being able to take a higher pressure it can take more air for its size. (You could say its more efficient for its bulk)
A regulator could be more efficient in its operation - but that's to do with its refresh rate, how quickly you can keep firing and for how long. But with rof caps most players won't notice
£ for air quantity and £ for life, a 3000psi cylinder is always more value for money - even if you throw it away at the 5 year point
Fibre cylinders aren't always lighter - of course you are right for an equivalent comparison. If two cylinders are the same size the fibre is lighter. But if you take a 'standard' 3000psi and a 'standard' fibre then you will find the 3000psi is the same, lighter or pretty close (because the standard fibre is bigger and bulkier)
If you wanted light back then what you needed was a disposable Stako - new every 5 years, so you were paying serious money to get the weight saving, now you can buy retestable similar light cylinders
Balance is more important then weight anyway
Fibres are best for weight at a given size/capacity, choice of size and shape - if you don't get the right bottle ergonomicaly for you then you just waste over £100 extra on the cost of a cylinder
In addition it's also more fragile. One bump or scratch can mean either binning the cylinder or paying around £25 on an extra inspection and hydro test for piece of mind of safety