Stands have superpowers, but they don't usually effect the user. It is possible for a stand to disobey the user and just not use the power at any moment, but that kind of thing usually doesn't happen.

A main character in part 3, Polnareff, had super speed as a power. He wasn't capable of running fast, just his stand, Silver chariot, was. He made up for it by using quick swordplay and feinting a lot.

As a rule, you can have wierd looking stands. One memorable stand, Made in Heaven, was a dude with a horse coming out of his crotch. Cream Starter was a can of aerosol which sprayed human flesh for patching up cuts. Strength was a freakin' industrial carrier ship. The Emperor was a gun that shot homing bullets, Hermit purple was just tentacles. 

Of course, if you do set out that way, you're gonna be at a disadvantage. You can't move a ship over land, or block anything with a spray can. Quite a lot of jojo shows that having a strong stand with a weak power is a whole lot better then having a tiny ineffective stand that does one thing very well. 

The best and most powerful stands are kooky, abstract, and just plain wierd.