Which brand as per you has the best x58?
Gigabyte , EVGA , XFX , MSI .. which one?
I saw the specs , think the Gigabyte one supports RAM upto 2000Mhz on the other hand the EVGA one supports upto 1600Mhz.. True?
Change the title, dude! X58 is the common chipset in all the above MoBos. 
If I’m not wrong… ASUS P6T (or similar name) supports 1800MHz ram, not sure which one is the best from brands you mentioned. Ideally wait for someone to do a complete shootout of top-end X58 boards. I think Anandtech has one such article in pipeline. That should give you fair idea. As of now, Gigabyte boards seem to be feature rich but the pricing in India will be ridiculous. Asus has their own offerings praised by many users while EVGA is also gaining momentum with their X58 offering. Then again there is Foxconn’s beauty, Bloodrage.
All in all, it seems that X58 itself is rocking chipset. Either of the boards should be good choice to buy (depending on availability and price of-course), if that’s what you’re looking for.
afaik, currently evga, dfi > asus, gigabyte > remaining companies