Why not LG? (Im just curious) Its the third largest mobile manufacturer after Samsung and Apple, manufactures the Nexus 4 for Google, has vfm products, is very reliable
If it werent for the fact that you dont want a LG device, the Optimus L9 would be the best phone you could get. Its the best under 20k.
Dual-core A9, 1GB RAM, 4GB internal memory, Jellybean update ready, stunning IPS HD display, expandable memory, dual cam, 5mp cam with HD recording, its even got WIFI direct! No other device offers such a feature set for under 20k.
In the end its your choice, out of the list you specified, the Samsung S Advance is the best.