I'm confused to choosing softwere between solid works and NX 10 which is more useful?

If you are looking for PLM software/ Complex surfacing go for NX, If your use is limited to design, Drafting and assembly Solidworks is best.

This is a professional comparison...
Check it out:
https://www.g2crowd.com/compare/design-to-siemens-nx-vs-solidworks

Really depends on the work you're doing.

If these were my preferences...

Collaborative, large assembly projects?
Top-down assembly?
One package for CAD/CAM/CAE?
The need for Sub-d modeling (Realize Shape module) within a parametric environment?
Synchronous modeling?
Surface models to Class-A modeling tolerances? (If you're looking to primarily model to Class-A, neither option would be my first choice)

NX

For everything else?

SWorks

For Surface Modelling and Complex application NX is Best , For Die Design , Drafting , Assembly work Solidwork is Best and Easy Software.