Looks like the Flickr team is on top of the biggest issue with the official client: a nice black screen upon launch. While it doesn't happen every time, it's enough that we've heard quite a few complaints from users about it. In v1.3, we also see a few other bug fixes/additions which are welcomed:
- Fix problem with blank screen during startup phase for some users
- Fix for application error when sharing from media hub with a large number of photos
- Background photos on home panorama now change from time to time
Let us know in comments now if this app is up to standards. We already think of it as one of the best to represent WP7, but it's even better without that glaring aforementioned issue, no? And considering we just got v1.2 last week, it looks like Flickr is actively engaged with this app. Grab it here in the Marketplace.