I use google chrome and application went ok. Arrived in post 3 days later and activated with no problem, even managed to change pin number.
I ordered one because Ryanair just opened up Edinburgh - Murcia with cheap flights. Flight prices have started to rise already though.
When ordering card I had to ensure I was on the uk site (£6 for card) and not Irish site. Card has different conditions and Irish one appears more expensive. £6 fee discounted off first flight price with voucher. It is amazing to use Ryanair and not be stung for extra £££££s at the end of booking.
Card conditions are just like Ryanair, stick to Michael's rules and it will be great value but break them at your peril.