Avoid the Tulip crane in particular. If it's on rails, forget it. It will tip over.
All small cranes have a narrow base, and standing up on the platform raises the eg. of the whole crane. A higher than designed for e.g. and a small wheelbase is too tempting for the gods of physics. A little wiggle by you or a grip pushing the base far from the old c.g. will cause the crane to come down.
I learned this lesson the very hard way. In spite of listening to - and repeating - many stories of near disasters, I once got on a Tulip crane.
I was told a different crane was going to show up on set, but there it was, and nothing else was available. I was going to be silling and not standing. Garrett ...