Both have their advantages. As a stallion, I have my strength, I'm taller, and Wild is actually physically attracted to me. As a mare, I'm a lot quicker, I don't eat or drink as much, and I look ADORABLE with a ponytail.
That was my first assumption but you know what they say about those. I take it you like how the hair from the Rockette/Little Sneaky(sp) fusion looked? I thought it looked cool too.
Have you seen these and what do you think of them? http://inspectornills.deviantart.com/gallery/52926574/Transformers-Ponies-Mashups
Since I have permission to answer stuff.... Rockout's default form is a mare. He needs medicine to change back. It used to be he needed to take it before going to sleep to be stallion the next day. Now with the new formula he changes back instantly and it last for twenty-four hours. This only aplies to Equstria Rockout. EG Rockout at present has no means of returning male.
Lioconvoy's got it right. His answer is right below. I've started taking it in the mornings so I can be a guy at night. It's cool. A couple of users have before so I don't mind.