Predator is a very good antitank.
He only needs a way to hit the enemy and attackspeed => Something like Frostwolf's skull, Charged Hammer and Deamonic Breastplate work fine.
i keep trying to play with Swiftblade, Predator, Pyro and Hag... maybe couple mounths i get way to play "good"... i think magebane a little distant to play in this moment... i need more experience on game to play better...
jungling with pred never works out well, especially if you get mino/catman spawns, which completely screw you over. even against smaller camps, like someone above said, you'll be forced to put all your points into your lifesteal, severely hindering your ganking ability for the next few levels. you'll either have a weak leap, or a short magic immunity/armor buff. lane pred is amazingly good, you don't even need that great of a babysitter because of your small amount of lifesteal + magic immunity. his leap+slow paired with a good stun is almost a guaranteed kill. at a higher level jungles tend to be warded anyways, especially if the opposing team realizes that pred is jungling.
another thing i must add about jungling, any hero that forces himself to take damage while jungling (lego/pred/ctulo) is at a major disadvantage when people come to gank you. if they choose the best moment, you may be at 100 hp, and 2 hits from getting that catman kill. you can kill him and go heal, but if they see you, you're dead. with jungles like wb/tree/temp, the hero itself doesn't take damage making it easier to escape.
on topic, my best hard carry is magebane, semi-good reactions + 320 base movement speed makes you very hard to gank.
"Yeah, the ideia to use Predator is valid but i need to learn jungle first... and magebane i've some problems with him because in the beginning he doesnt have skill to inflict damage..."
You don't jungle pred other wise you will be spending 20 mins of the game doing nothing but farming... Besides he is a very good laner with a support. Magebane does have skill to inflict damage if you read his techs properly. His First ability should be maxed first as not only it provides a mana drain with just simply attacking the enemy it also deals additional damage to how much mana is drained which makes him an amazing lane bully. His ulti is a great finisher on enemies as well which perfectly compliments his first skill. (this renders your point about magebane invalid)
I will have some use of you
Madman is a great choice. He has a low cooldown, low mana cost escape and big nuke/slow for the early game, and his passive and ultimate are amazing damage and attackspeed steroids for the late game. You only need a shrunken and shieldbreaker to tear apart teams with MM and any additional items are a bonus. I really don't know why he isn't picked more, he's fantastic, and easy to play, and (relatively) effective with not a lot of farm.