Will is spot on re Specsavers - Daughter has them and loves them. If you are planning the prescription route they are the best option by far (in my opinion).
My eyes are too bad for prescription glasses so its contact lenses. Pillas are the best. Tried most of the others but ended up with the Pillas. I have same 580's (non-precription versionf o the 560) which are not as good as the current Panthers. Oakleys are Ok and i would not discount the TR45 lenses which are the choice of the American Military.
Pilla-owner here as well. Sort-of a buy once, cry once choice really. I can't fault the quality and while the plethora of options may seem daunting at first i have tried different lenses (of other people) over the years to narrow down my choices. While certainly not cheap, having a few different options in the bag does help me adapt to conditions that would be more challenging without. May be all mental (as for most expenses in the sport) but for me it's worth my pennies.