dear Vamsi first you may need to define what "better" means or what the important criteria are. 3d printing for single parts and design studies and changes is much more flexible as you do not need to manufacture extra tools. on the other hand size and shape deviations as well as material quality as manufactured may turn out to be a problem for the printed material as the high temperature gradients in the solidification as well as the frequent local re-melting by printing the next layer could lead to very different material properties with often very high residual stresses. For which heat treatment of 3d printed parts is indispensible to end up with a useful part. I asume, if you want to manufacture a large lot of parts the material quality and hence also strength of powder sintered parts will be better, respectively high, or even much higher than of printed ones.

Each method (Sintering in 3d printing or Sintering in powder metallurgy ) has special procedure and approach to perform process and related with parameters (Materials type,temperature , compacted force , grain size.....).

The definition of sintering implies subjecting a powder preform to heat treatment below (usually 0.6 Tm) the melting point of the major constituent in order to impart it strength and integrity. The agglomerate in the mean time develops grain boundaries as the contact surfaces change from non metallic to metallic in metals. (In polymers the extension of chains across the connecting grains is the complimentary imperative).

Since the concept is similar in 3-D and/ or in sintering in powder metallurgy, there is no theoretical difference. However, the operative mechanisms can be differently applied.