I've had several Windows Phones in the past, starting with the OG Samsung Focus and most recently the 925 on T-Mo. I've also had several Android phones and right now my daily driver is a Nexus 5. As I currently don't have a WP and I'm starting to get the itch again, I thought I'd do a quick survey of app availability on WP based on what I consider "core" apps on my Nexus 5 (i.e. apps that I open weekly, if not daily). Thought it might be interesting to share the results 
High level, it's only getting better. If you don't include Google Apps (for which I've essentially given up hope for official apps), nearly 2/3 of my core apps have official clients and only 1 is completely unavailable in any way:
[TABLE="width: 500"]
[TR]
[TD]WP Availability[/TD]
[TD]Count[/TD]
[TD]Percent[/TD]
[/TR]
[TR]
[TD]Official app
[/TD]
[TD]17[/TD]
[TD]63%[/TD]
[/TR]
[TR]
[TD]Alternate app/service[/TD]
[TD]4[/TD]
[TD]15%[/TD]
[/TR]
[TR]
[TD]Mobile site[/TD]
[TD]3[/TD]
[TD]11%[/TD]
[/TR]
[TR]
[TD]3rd party client[/TD]
[TD]2[/TD]
[TD]7%[/TD]
[/TR]
[TR]
[TD]unavailable[/TD]
[TD]1[/TD]
[TD]4%[/TD]
[/TR]
[TR]
[TD]Grand Total[/TD]
[TD]27[/TD]
[TD]100%[/TD]
[/TR]
[/TABLE]
Now, if you include Google apps:
[TABLE="width: 500"]
[TR]
[TD]WP Availability[/TD]
[TD]Count[/TD]
[TD]Percent[/TD]
[/TR]
[TR]
[TD]Official app
[/TD]
[TD]17[/TD]
[TD]47%[/TD]
[/TR]
[TR]
[TD]3rd party client[/TD]
[TD]8[/TD]
[TD]22%[/TD]
[/TR]
[TR]
[TD]Alternate app/service[/TD]
[TD]6[/TD]
[TD]17%[/TD]
[/TR]
[TR]
[TD]Mobile site[/TD]
[TD]3[/TD]
[TD]8%[/TD]
[/TR]
[TR]
[TD]unavailable[/TD]
[TD]2[/TD]
[TD]6%[/TD]
[/TR]
[TR]
[TD]Grand Total[/TD]
[TD]36%[/TD]
[TD]100%[/TD]
[/TR]
[/TABLE]
Is it ideal? No...but as I said it's a lot better than it was and I only expect it to grow. I would note that for a couple of the apps that are "3rd party" or unavailable, the Android app is garbage too (Goodreads, Safeway)...so clearly they don't have a very good non-iOS focus. Additionally, the services marked as "mobile site" are really well done such that when paired with the WP app "WebApps," you'll hardly know the difference since the Android app is simply the mobile site in an app wrapper anyway. Here's the full list of my "core" apps if you're curious:
Point is, I think I'll be taking the plunge again with the 1020
Are there any great official apps, well done official web apps, or great 3rd party clients that you really like? I'm interested to hear what everyone's "core" apps/services are, particularly if you moved from iOS or Android and had to migrate to the new ecosystem.

High level, it's only getting better. If you don't include Google Apps (for which I've essentially given up hope for official apps), nearly 2/3 of my core apps have official clients and only 1 is completely unavailable in any way:
[TABLE="width: 500"]
[TR]
[TD]WP Availability[/TD]
[TD]Count[/TD]
[TD]Percent[/TD]
[/TR]
[TR]
[TD]Official app
[/TD]
[TD]17[/TD]
[TD]63%[/TD]
[/TR]
[TR]
[TD]Alternate app/service[/TD]
[TD]4[/TD]
[TD]15%[/TD]
[/TR]
[TR]
[TD]Mobile site[/TD]
[TD]3[/TD]
[TD]11%[/TD]
[/TR]
[TR]
[TD]3rd party client[/TD]
[TD]2[/TD]
[TD]7%[/TD]
[/TR]
[TR]
[TD]unavailable[/TD]
[TD]1[/TD]
[TD]4%[/TD]
[/TR]
[TR]
[TD]Grand Total[/TD]
[TD]27[/TD]
[TD]100%[/TD]
[/TR]
[/TABLE]
Now, if you include Google apps:
[TABLE="width: 500"]
[TR]
[TD]WP Availability[/TD]
[TD]Count[/TD]
[TD]Percent[/TD]
[/TR]
[TR]
[TD]Official app
[/TD]
[TD]17[/TD]
[TD]47%[/TD]
[/TR]
[TR]
[TD]3rd party client[/TD]
[TD]8[/TD]
[TD]22%[/TD]
[/TR]
[TR]
[TD]Alternate app/service[/TD]
[TD]6[/TD]
[TD]17%[/TD]
[/TR]
[TR]
[TD]Mobile site[/TD]
[TD]3[/TD]
[TD]8%[/TD]
[/TR]
[TR]
[TD]unavailable[/TD]
[TD]2[/TD]
[TD]6%[/TD]
[/TR]
[TR]
[TD]Grand Total[/TD]
[TD]36%[/TD]
[TD]100%[/TD]
[/TR]
[/TABLE]
Is it ideal? No...but as I said it's a lot better than it was and I only expect it to grow. I would note that for a couple of the apps that are "3rd party" or unavailable, the Android app is garbage too (Goodreads, Safeway)...so clearly they don't have a very good non-iOS focus. Additionally, the services marked as "mobile site" are really well done such that when paired with the WP app "WebApps," you'll hardly know the difference since the Android app is simply the mobile site in an app wrapper anyway. Here's the full list of my "core" apps if you're curious:
Android | WP8 | 3rd Party App or Mobile Site |
Amazon | Official | |
Audible | Official | |
Bank of America | Official | |
Capital One | Mobile Site | moblprod.capitalone.com |
eBay | Official | |
Evernote | Official | |
Expensify | Official | |
Official | ||
Gmail | 3rd party | MetroMail |
Goodreads | 3rd party | Social Reads |
Google+ | 3rd party | (nothing good) |
Google Drive | 3rd party | Google Drive on WP |
Google Maps | Alternate | Waze |
Google One Today | unavailable | |
Google Play Music | 3rd party | CloudMuzik (get beta from dev) |
Google Translate | Alternate | Bing Translator |
Google Voice | 3rd party | MetroTalk |
Hangouts | 3rd party | IM+ Pro |
IMDB | Official | |
Official | ||
LastPass | Official | |
Lift | Mobile Site | www.lift.do |
Mint | Official | |
MyFitnessPal | Official | |
PayPal | Official | |
PocketCasts | Alternate | Podcast Lounge (...waiting for 8.1's new app) |
Press | Alternate | Nextgen Reader or Phonly |
Safeway | unavailable | |
Skype | Official | |
Speedtest.net | Official | |
Talkatone (receive VoIP) | Alternate | Skype (paid) or Viber |
Trello | Mobile Site | www.trello.com |
Official | ||
Windows Phone Central | Official | |
Yahoo Sports | Alternate | Bing Sports |
YouTube | 3rd party | MetroTube or others |
Point is, I think I'll be taking the plunge again with the 1020
