It's hard to say because specs aren't everything, and the 830 has a better camera for several reasons despite having 3 less megapixels, also the 830 has the usual Lumia benefits such as a clearblack display that works good in sunlight,and delivers deep blacks,
super sensitive touch, and the os vendor is also the manufacturer which means better support..also the 830 will stay smooth throughout future updates, while the 1+1 since it runs android will most likely slow down eventually,because andoid always needs the latest super powered internals to run smooth..also it depends on which design u like more ..the 830's aluminum rim,curved front black glass,and colorful removable backs or the one plus ones design..and also the one plus has a bigger battery but that doesn't necessarily mean longer use because it runs a heavier os,with a larger screen and pixel density which all affect battery life..