Uniform extent allocation is a good idea to use if most of your segments are of same size. But, it is not good idea if size of your segments range over a value from few mbs to gbs. In this case, either you have to allocate more space for smaller segments by giving bigger uniform size at tablespace level or have more number of extents for bigger segments by giving smaller uniform value at tablespace level.

Auto allocate is good idea if you dont want to control the size of your extents.

My idea to combine advantages of DMT as well LMT is something like this..

Create your tablespaces as DMT and use dbms_space_admin package to conver them to LMTs. This makes the tablespaces LMTs and at the same time extent management remains as user. User extent management allows us to create segments with our own extent size. This gives us more control over extent size as well as reduces contention to data dictionary by using bitmap segments to manage space allocation issues.