Ursa - probably a lot of people are still just using their old builds, since the buff is still relatively new. I might be tempted to stick to a 
Morbid Mask for a long while early and get up 
Phase Boots and 
Blink Dagger before upgrading it and delay my choice of orb for as long as possible. Else I would be tempted to go 
Vladmir's Offering + 
Orb of Venom early.
Ursa's life very difficult. Ursa is pretty squishy early, and he can't contribute anything in a fight unless he can auto attack. Ursa needs Vladmir's Offering, Blink Dagger/
Shadow Blade and 
Black King Bar before he can really contribute to fights other than running up to people his team chain stuns. If you can delay those items for a while, you can get items of your own to deal with him. 
Roshan at level 4 several times and it seems like it's all down to luck. 
Healing Salve, 
Tangos and 
Stout Shield, then at level 4 I pick Morbid Mask and according to the guides I should be able to solo Roshan,
yet I end up having almost no HP while Roshan still has a half of his. When is it safe to attempt to kill Roshan early? What am I missing?
