Android VS. WP is truly an excercise in strengths VS. weaknesses in OS's.
Are you a huge app user or think you will be? Deal breaker- go Android. MS has done a wonderful job building up the WP app selection, but from local apps to games and apps arriving first, Android has it all over WP still.
Do you get bored, love tinkering with things, are into playing around with those little things that make a smart phone smart, then Android wins.
Multitasking, changing keyboards, so on so forth. This is what makes Android the success it is.
Do you like to set up your phone to basically work, and have it work for you everytime the same way you last left it? WP wins. Android has got this strange quirk about people saying a lot of "HUH?" and "Why won't it load up this?", no matter the device or the premium or budget set up. WP tends to be more atable, even after constant use over long periods of time.
Seamless, smooth operations? Look, I like Android, but over time even the best of those devices- and the Note 3 is among the best- require a lot of tinkering to keep moving efficiently. Open apps in multitasking modes, UI's that slowly add to the device having a stutter or a sputter, updates that make existing tasks slower, background apps that run without you knowing it, and about a dozen other aspects of Android all contribute to a phone that after a year is not the same joy to use that it was when you bought it. There are background tasks to control in WP as well, but they are easily managed and disposed of if you want. It is designed to allow long term operation, and the lack of UI a lot of people site as a reason to not like WP is the reason updates generally work smoother and with less negative effects on it.
Support? Samsung is good at supporting their top end devices, so while Nokia is among the best, this may be a wash with the Note 3. I had decent support with my Samsung WP7. My wife has had a couple of firmware updates and an OS update on her Note 1. Nokia and MS have done a fantastic job supporting ALL their devices, though. So I stillI give the nod to Nokia/MS, but not by much.
The Note 3 stylist is a great tool, only found on it. It's split screen options are great. It is more pocketable.
The L1520 has an amazing screen, it's camera and battery are both regarded in most reviews as better then the Note 3, and Lumias are basically sherman tanks with phone guts ut in them. Lift up a L1520 and a Note 3 at the same time, and the feel of the L1520 just screams winner of the local "Tuff Man" contest.
Tools: Google Maps are still the best, and intergration with Google services are a handy thing.
WP has both Nokia Maps and Bing Maps (I prefer Nokia maps), Office built in, and the exclusive apps on Nokia WPs are a blast.
Also, I suggest investing in whatever ecosystem you grab the smartphone on. Google services have a great relationship with Android phones (duh), and the more you invest in Microsoft services (Outlook, Skydrive, XBOX Services, so on) the better you will enjoy a WP phone.
Let us know what you decide!!