Having a viable alternative to the KHTML-lineage engines (blink/webkit) besides Gecko will be a boon for the web.

I haven't been super happy with Mozilla's management of Firefox, although it's my daily driver and a great browser. I just don't have super high confidence it'll be viable long term from a corporate standpoint, especially since it's largely been payrolled by Google which makes Blink, so having another real alternative would be great. Having a sustainable, grassroots community project in Servo makes me have hope again (after Mozilla dropped the ball on them...)