Azureus rocksss
I tried Bitcomet, utorrent.
Bitcomet has consistent speed but uploading speed doesnt go beyond particular limit even though having a helthy torrent and capacity.
utorrent -I experienced very rare simultaneos upload.
+ pont is it consumes less ram and also ocuupies less space .
But both bitcomet and utorrent has very less features as compared to Azureus.
Just configure settings and njoy Leeching and Seeding on Azureus, never find any prob. till now.