I have owned both the Avatar 212 Neo and the Legion 212 cabs. Sound-wise, I would say they are extremely similar. If anything, the Madison drivers provide a little more low end punch than the Avatar, but it's pretty close. The Avatar also has an adjustable tweeter, which is nice for upright bass slappers like myself. The tweeter and hardware on the Avatar are superior to the Legion. You get your savings on the Legion in cheaper components (except for the Madison drivers - they rock!) and customer service.
Dave at Avatar is arguably the best in the biz for customer service. Music Supply Center is great to deal with if you never have any problems with your cabinet. They will most likely ship it in a timely manner, but you can forget about them answering the phone and their email response is spotty at best.
I like my Legion 212, have been battling with them for over TWO MONTHS about shipping out my replacement tweeter for my 212. It was defective, I shipped it back and it's been shipping out "tomorrow" since December.
Nice sounding cabinet, probably the best for the money that you will find. Zero post-sale support. I suppose that's the trade-off.