When i say lip or ledge i mean basically the same thing. Just a ledge raised a little on the cone off the bottom like seen in the link below. Just to catch any eggs or fry that might fall off the cone.
http://www.azdiscus.com/images/breedingcone.jpg
Its really a luxury for me, and I'd probably end up buying either way but it seems hard to find good cones with lips/ledges. Not being a potter, I have no idea on how much extra work it takes or how much more production time is involved, but thats what I as a consumer would like to see. But make a realativly cheap, good quality cone and i'll be interested.