I looked up demo's of them on youtube and the Mendini MV500 sound a whole lot better than the oher two. So if it was me having to choose between those 3, that is what I'd go for. 
BUT, where do you live and how much are you willing to pay for your first instrument? 
Is the violin something you already know you'll want to stick to, or do you want to try it out first? If you just want to try it out, I suggest renting for a month or two first. That should make you able to decide if you like it or not. (You will LOVE it! :P)

If you'd want to continue, it is wise to spend a bit more (if you are able of course)on a better instrument instead of buying something cheaper that you'll grow out of fairly quickly, and then spend more on a better instrument. Is more money spent in the end that way.
If you live in USA, I really recommend at least contacting Fiddlershop. (or if money and importcosts are no problem, doesn't matter where you are. I live in sweden and bought their Soloist outfit as my first instrument and paid 30% extra in duty and taxes. But worth it to me as it'll probably be the only instrument I ever buy, and I was 100% sure I would get something good)

They have quality instruments and customers love them. They have beginner outfits that have great reviews from customers. For example, the concert violin outfit is one that I've seen a lot of people choose as their first violin. (And just a few months later decide to upgrade to another one of FM's violins, that's how happy they are with them :P) 
You get a great instrument to begin with that you'll be satisfied with for a while, plus everything else you need. Like rosin, shoulderrest, bow etc. You can even make special requests in your order, like video demo for approval, or if you want a certain type of sound. Tell them what you're after and they'll find it for you.  

I'm rambling here lol, but anyway. If you're set on choosing between one of the 3 you listed, I would go for the Mendini.