Skymiles or Flying Club ?

I use Delta enough to regularly make Skymiles Ag and now have the chance to use Virgin too. I was wondering whether to start using Flying Club instead or just keep on adding to my Skymiles account?

My concern with Skymiles is being charged miles and more £££ than the airfare when I tried to use them on KLM. After this I started using Flying Blue to collect points on DL to use on KL but this is not an option for VS metal.

Thoughts? Is it worth joining Flying Club?

I believe that DL miles/status is revenue based rather than flown miles whereas VS still reward based on miles (although status comes with TP but if you fly DL domestically this will be easy to attain).
VS is the only carrier I am aware of that allow double upgrades meaning you can upgrade form economy to Premium or into UC.

Well I went with Flying Club and so far all my miles got posted correctly which is great.

I also set my Virgin Trains East Coast to add to my Flying Club account so I get a few extra miles when I travel down to LHR.

On my next trip I am Virgin R class on the next DL operated flights so I am not sure if I get miles/tier points or not.

VS is the only carrier I am aware of that allow double upgrades meaning you can upgrade form economy to Premium or into UC.

I know this is held up as advantageous, but in reality the upgradable ticket needed to do this will likely cost close to a discounted version of the next fare up. So who'd buy an upgradable economy and upgrade to PE? Add the taxes/surcharges and you can buy a K outside the sale...

So, like the 2 for 1 on the credit card, this is a case of VS marketing style over substance...