Nokia Maps has been bumped to version 188.8.131.52, which introduces improvements to stability and performance. When firing up the app on a Lumia Windows Phone it no longer takes noticeably longer than Bing Maps--in fact we're only seeing about a one-second speed advantage now with Bing Maps for load time.
As well as the optimizations applied, the team has reported that Microsoft also addressed the Windows Phone Store issue. Those who were hit by the "Problem with app" dialogue that persisted showed when attempting to load the application will be pleased to hear that this update addresses that very issue.
It's good to see Nokia continuing to develop and expand its services for its Lumia family of Windows Phones. The company recently announced a branding change for its mapping and location services, which will be marketed under the HERE umbrella.
You can download Nokia Maps from the Windows Phone Store (using a Lumia device).