I have a protein with lack of structure. I would like to get model as soon as possible because I utilized robetta, but it was taking a long time and I tasser results not satisfied. So help me out of this problem.
Phyre2 is faster than I-Tasser, but I-Tasser is still one of the best modeling servers available.
Check out the results from the 2012 CASP10 meeting and the 2014 CASP11 meeting. This is a great place to see side by side comparisons of the available bioinformatic servers.
From my experience, Robetta is good enough, though it takes time. If you want to get the model asap, use either Phyre2 as suggested by the researchers above or Swiss Model (http://swissmodel.expasy.org/) or you can also use Modeller. Modeller is a bit complicated as it requires the knowledge of Python but it's GUI is available on http://modellergui.blogspot.ch/ which is easy to install and use. For Easy Modeller, the original version of modeller (https://salilab.org/modeller/) and python package should be installed to execute it. The modeling of the protein is very fast and reliable.
BioSerf v2.0 (Automated Homology Modelling) is a Automated homology and de-novo modelling server, utilising Modeller, PSIBLAST, pGenTHREADER and HHBlits. Has worked for me very well . You can find it at http://bioinf.cs.ucl.ac.uk/psipred/.