I am an absolute Arai Addict since they first came into the country, always have multiple Arai's on the go as Pic shows, but I bought a X-lite Carbon RR and I wouldn't go back, I literally have to force myself to wear the Arai's as I have so many to wear out.
I'd say the X-Lite is better than the Arai in every way. The stand out points are:
1. The X-Lite is far lighter and that just helps your ride in everyway. I feel so much fresher after 300-400 miles in all weathers.
2. If you do trackways the helmet opening is higher and wider which in a crouch means your not cranking your neck up as much as you would with the Arai. Bottoms lower so fine on the road.
3. Lining. Strange colour green but it sure does work. Far less sweating and less irritation on a long day.
4. Visor changing how it should be done, even better than Shoei
5. Ventilation as good as an RX7 but quieter.
They've just been bought out by Shark who themselves make good lids, so I see them going from strength to strength.