LV you can take day through night, and would be great if you had a lot of informal things to do like school, shop, hanging out. I think the Prada seems more like a night time accessory and it's a bit more formal, like to dinner and movie.
My LV Speedy 30 is my most used bag. I can't get into Prada to be honest. The made in China thing drives me crazy. But I also don't feel like the quality is as good - maybe it used to be, but not anymore. While LV is going downhill, it hasn't been as fast as Prada.
My practical side is saying LV...(I love my speedy SO much). The prada is adorable tho... Think about what you really need it for OR don't think and get whichever one is tugging at you....I'm gonna say louis cus cute as that prada is, I'm not feeling it.
The Prada you have is stunning but may not work better as an everyday bag if that is what your needs are calling for. Also, although basic black is something we all can use and a personal favorite, depending on where you reside, it may not work during the warmer months.
The Louis Vuitton Damier Azur Speedys frame and pattern make it an easy preference to use nearly anywhere and any season. There is ample room for all the necessities and the material is weather resistant.