JSF advantages:
Day 1 Stealth
Flies from a boat
JSF drawbacks (even if we negotiate the tech transfer we require):
Already likely to be more expensive in pure cash terms than Typhoon, and without the same industrial/employment/balance of payments benefits
By comparison with extra Typhoons (or even navalised Typhoons) JSF will require a new and separate maintenance and support infrastructure. In a 12 squadron FJ force will we need two or even three types?
Unlikely to be integrated with many of our core future weapons
Unlikely to meet planned its planned ISD, and Harrier unlikely to be able to extend to fill the resulting gap
Neither a true multi-role nor a true swing role aircraft
Stealth may be yesterday's technology - did the F-117 loss and F-117 hull loss in the Balkans signal this?
Still an unproven and very high risk programme, with 99% of the flight test programme still to do
It won't be "the best available platform to conduct ops of the future" if we don't have operational sovereignty. It won't be operationally useful if we can't support and sustain ops without LM and the USA's say so, and if we can't integrate weapons and kits via UORs, or if we don't have the necessary clearances to repair birdstrike or combat damage to the clever leading edges, and the kit to test the RCS of repaired areas.
Even if we have a full-up F-35 and everything we need to operate it without restriction, its one unique capability (day one) can probably be better served up via TLAM and stand off weapons.
And there's a real doubt in my mind that it will be affordable. Only an incurable optimist (or the truly gullible) would still swallow Lockmart's stated prices.