Not really, if you want performance gains outside of a primary key and it is modelable with an index, then you still want mnesia or a database. 
ETS really is just like a map, a linear search over an utterly massive set of data might be faster in ETS but I doubt it is by much (and if you are reaching that, then a database should be used instead).
EDIT: Ah hah, I knew I remembered a thread where someone benchmarked between ETS and Maps and showed that ETS was about 1.93x slower than maps at a size of 100_000 elements (so quite huge, and that difference held pretty much true among all size of elements tested), not even a factor away in speed difference: Benchmarking lookup time for map vs ets
