Having 4G LTE as an option is a plus if you need it,most would pass on that option.
The battery life on the Surface 2 is superior to the 2520, which battery life is based on having the screen at less than optimal brightness settings.
The difference in screen is great for reviews,but the reality is both are great looking,but only the Surface screen functions properly. Here maps isn't anything to write home about, Bing maps is just as usable. But there is nothing about the 2520 that comes close to the innovation that is built into the Surface 2.
Responding in order of posting:
1. "Having 4G LTE as an option is a plus if you need it,most would pass on that option."
The Cellular modem is one of the stronger arguments for the 2520. Every Surface/Surface Pro/Surface 2/Surface 2 Pro owner I've ever met has wistfully stated that they wished for a model that had a cellular modem option.
2. "The battery life on the Surface 2 is superior to the 2520, which battery life is based on having the screen at less than optimal brightness settings."
http://winsupersite.com/mobile-devices/lumia-2520-vs-surface-2-understanding-trade-offs To quote Paul Thurott, who's rather on top of the industry when it comes to calling out advantages/disadvantages in the Windows market:
"
Battery life. Neither of these devices is any slouch, and both will soon have additional battery life offerings via special keyboard adapters. We need to give the Lumia 2520 a slight edge on battery, but I don't think this will matter much in the real world. Still: Lumia 2520 for the win."
So you should probably take the argument about battery life out of the equation. When that "large, cumbersome" keyboard releases, the battery life on the 2520 will outstrip the Surface 2 by a HUGE margin since there is no comparable power option available for the Surface 2.
3. "The difference in screen is great for reviews,but the reality is both are great looking,but only the Surface screen functions properly"
This is an opinion and not a fact. For some, the screen on the 2520 looks awesome and operates properly. I'm sorry that you have had a bad experience but it's just not accurate to say that one is better than the other without some kind of facts behind it. Right now, there are only guesses and conjecture around the causes which can include problems in the OS itself.
4. "Here maps isn't anything to write home about, Bing maps is just as usable. But there is nothing about the 2520 that comes close to the innovation that is built into the Surface 2."
I'm lumping your last two statements together. Once again, those are purely your own opinion, possibly darkened by your own poor experience with the device. I cannot blame you for being frustrated but not everyone has had a bad experience as you have. Your opinion is that the Surface 2 is better than the 2520 - That was clear from the other post to this thread that now appears to have been deleted. I hope that you are able to purchase a Surface 2 and enjoy that device because it is, indeed, a worthy purchase. But so is the Nokia Lumia 2520. It just wasn't the right one for you.