What means "personal"? Do you do it mainly for the fun or for the money? If it's the second, it's a no brainer. Use the tools you know and focus on you problem

What means "personal"? Do you do it mainly for the fun or for the money? If it's the second, it's a no brainer. Use the tools you know and focus on you problem domain. If its an experiment or an exploratory project, well, use whatever appeals to you.