To begin with excuses like "I'm not good at using Armlet" are kind of ridiculous. Simply using it more will make you familiar with its uses. Ofc there are some cases where armlet might be a bad choice specifically against several DoT spells, but for its cost and buildup it offers to str heroes that need DPS what no other item does, burst EHP and DPS in a very low price.
Anyway, if you insist in not using it, Diffusal goes well if you're playing like a ganker and also need firepower vs heroes, Manta also works very well on him, all stats and IAS and ms are very good, so are the illusions with his very good base stats.
Generally if for whatever reason you need to have a more passive itemset, I'd suggest Hot->Fly for uber extra carrying illusions.
Battlefury/Vlads is crap on him, Desolator/Radiance slightly above crap and Satanic mediocre at best, though it's good if you seem to not rely on your illusions too much.
I hope you know how to play him early on with QB -> Stick -> Bottle -> Wand -> Treads and optional Bracers then gank,gank,gank till you're fed to get your big owning items.