Well, here's the rundown of all the Windows Phones I've had so far.
• Lumia 520: Strikingly stable and smooth for having such low specs... and 8.1 made it even better because the 8GB storage was no problem then. What it did, it did VERY well. Unfortunately, lack of FFC and 512MB RAM killed it for me.
• Lumia 1020: Awesome phone with an awesome camera. Specs weren't the greatest, yet I can't say it's ever been caught lagging either. What killed this for me was the absolutely boneheaded decision to release a camera-oriented phone that had no expandable storage. They broke the cardinal rule of cameras right there. If the 1020 was planned out well enough to realize that it needed expandable storage, I'd still have it today.
• Lumia Icon: Nice size, very powerful phone, but again... they give you all the components to inspire you to care about installing high resource games, taking quality pictures and pushing the limits... then restrict how much you can do with the locked, non-expandable 32GB storage.
• Lumia 1520: I was ready to convince myself this phone wasn't too big after the icon. I just wanted a phone powerful enough to run high end games smoothly, and the space to do so... and the 1520 delivered. After a month or so of denial, it simply became very real that the phone was just too damn big.
• Lumia 820: This was the first entirely satisfying Windows Phone. It's size was right, it's low cost without omitting the FFC, it had expandable storage, 1GB RAM allowed it to run anything, and it was very smooth through and through. It's specs aren't high, not is it's screen resolution... but it's another case like the 1020 where it gracefully handled high end games anyway... and it's got something that every Windows Phone I owned before this lacked... BALANCE.
• Lumia 830: Shouldn't surprise anyone to see that this one is my choice for the best Windows Phone has to offer. It's balanced, light, has exceptional battery life and follows in the footsteps of the 820 in all the right ways while bumping up the screen res and giving us WiDi. I'll be sticking to this phone for a very long time.
TL;DR - Get the 830. It kicks *** and - is by far and large - the most balanced Windows Phone.