They are similar, but not as efficient. Different manufacturer. In the past, Avalons were quieter then Antminers as well but offered less efficiency for the price. Bitmain has cornered the market and of all the Asic manufacturers has been the one company that has thrived and survived.

You would think competition should be greater given that the demand is so high, but unfortunately, other companies are having a hard time competing for whatever reason. Hopefully though these will be able to bring about some much needed competition