I'm against the entire buying votes idea, it ends up coming down to a risk/reward situation where you have to decide if spending 0.1 bitcoin is worth getting Monero on an exchange so that the increased value to your holdings grows beyond the spent 0.1 bitcoin. And to me that sounds like a pump and dump coin, which isn't at all what Monero is about.
Of course you might not even be interested in such things (P&D) but to an outside observer it just reeks of P&D.
I'm not really a fan of Mintpal.
I know I'm not very smart in these things but I just see it as little more exposure for the coin. I like Mintpal, I definately prefer it over poloniex for example. I think the price would go up naturally if more people get interested in the coin, and it's good to have it on popular trading websites already when they do.