Irctc.co.in is the best portal to book train tickets. Only issue was with its loading time. But, to mention, it is far better than before. Earlier, it used to load for so much time. At that time, we need not even think about booking Tatkal tickets. By the time it gets loaded, all the tickets would be in waiting list.
But now, they have increased the servers and also they introduced good feature like different booking timings for A/C, Non A/C, etc.