Something that many traders might not be aware of is the fact that the generic 'trader ID' (which more or less everyone except RepEx uses) is disappearing in version 4.85 . If you want to continue using the largest category of trading ships (Adv. Train, Whale, Heavy Tanker) then you'll need to buy a trading faction ID such as Gateway, Republican and so on. This is because the independent/large ZOI IDs such as Zoner are limited to 3600 cargo - so you'll have to pick a trading corporation with a more limited ZOI.
Now of course this isn't worth doing until 4.85 is out and we see what trade routes are available. Picking a Bretonian trading corporation, for example, would turn out to be a pretty daft idea if most of 4.85's "multi stop" trade routes turn out to go through Kusari. Just bear in mind that you'll need to buy a faction ID, and fix your rep appropriately (no more Police tag!) once 4.85 comes out.
No longer active online due to a dwindling amount of non-PvP (trading, pirating, mining, etc.) fun in the new version.