Nokia Lumia 630 vs LG L70?

Solution
Out of the 2 i would with the lumia 630 as it has a better cpu and gpu combination, better screen and more storage. Although it doesn't have as much ram I am assuming you won't be doing much with it in the first place as these are only budget end. But there is always the problem of a lack of apps and the speed at which they update in windows so if you don't mind that then get the lumia.
Surely this is an Android v Windows Phone q...? That's the decision you need to make... The cheap Lumia phones running Windows Phone make for excellent cheap phones (i.e. they run Windows Phone really well, and make for good phones therefore) but what you lose with Windows Phone is the breadth of Apps

Basically, the Lumia is a great idea, if you're not too bothered about having every possible app.
 
Out of the 2 i would with the lumia 630 as it has a better cpu and gpu combination, better screen and more storage. Although it doesn't have as much ram I am assuming you won't be doing much with it in the first place as these are only budget end. But there is always the problem of a lack of apps and the speed at which they update in windows so if you don't mind that then get the lumia.
 
Solution
The overall features which Custom ROM gives can't match with the Android Stock ROM and Windows phone. Any mid-range phone with a custom ROM preferably Cyanogen can do the trick and will satisfy your needs as well.