I wouldn't necessarily agree with it being slow; you do need to be much more cautious of what you're doing. You don't have all the freely available overhead on a mobile device, or network, to load 30 css files and 14 JavaScript from 5 different servers all over the world.
Anytime someone mentions PhoneGap my first question is: do you really need an app? I'm of the opinion 95% of apps should have never been an app - it's a website, that is all. Your efforts would be more efficiently focused on building an awesome, responsive, website that serves your purpose. With that being said, if you absolutely must have an app - for a functional requirement - you can do a lot worse than PhoneGap and it's what I would choose (with native out of the question).
I wish Android would make it a lot easier, more intuitive, to add a website icon to your launcher. That, plus a decent "web store" like we have on Chrome Desktop and you'd see the app-boners disappear pretty quickly.