I was just there 10 days, got home 2 weeks ago. I've been to PV about 8-9 times (and other "resort" towns in mexico over 15 times) and never once felt unsafe. We ride the public buses, wander thru the streets/shops of downtown and the romantic zone with our kids at night... Etc.
Honestly I can't believe anyone would question the safety of PV. As with anywhere else, including right here in the US, it's all about choices, being aware, and planning ahead.
If you would vacation in New York, Las Vegas, etc, you would be smart, so be smart anywhere else too, kwim? Don't mean to be harsh, it's just how I feel.