I'm hearing great things about Sketch but haven't used it myself yet. Sketch fanboys, check out @Jonnotie's Sketch Resources site.
@alexbaldwin - have you made the switch yet? :)
I've just made my first high-fidelity UI mockup with Sketch. WOW! Used to do this in Photoshop, I'm sold.
One question to experts. How do you make icon libraries easily accessible within Sketch across projects? I liked FlatIcon Photoshop plugin (http://www.producthunt.co/posts/...), is there something like that for Sketch?
I L-O-V-E Sketch. It's a great tool even if you're not an experienced designer. I use it for both basic wireframes and full mockups. Can't imagine going back to any other mockup tools.
Product Hunt