azureus is a resource hog, if you don't mind wasting 300mbs+ of ram and about 5% of your cpu go ahead, utorrent is simple and as fast as azureus, however it is now owned by the mpaa 1.6.1 so use anything lower, azureus is mainly used to cheat trackers with fake ratios, also azureus distributed database(dht) is better for cuaring new peers, also azureus can allow you to load your own blocklist with the plug-in thus eliminating peerguardian. Azureus FTW if you dont mind the resources, Ut0r FTW if you want the same speeds but use almost no resources.
but forward the ports is most likley gonna give mo speed.
Main Page - AzureusWiki
if you go azureus check this out^^^^
also dont llimit your up which is problaly what youre doing set it appropriate for your connection its in the wiki somewhere the calculator
also your speed depends on what other peers are sharing if your getting stuff from isohunt your problaly gonna get crap speeds viruses etc.. use a private tracker with dedicated uploaders.
PM me if you need more help