Maybe I'm so noob i don't get it... so indulge me another noob qn.
25mm vs 20mm
f1.4 vs f1.7
Leica-whatever-whatever vs Lumix
The only real diff is who made it, and possibly (anecdotally) glass is better (less CA/etc based on track record)? 0.3 f's can't be worth that much, can it? :S...