I've got an application that does user provisioning for Google apps (specialty provisioning).
I got to thinking, instead of going into the developer console for each customer currently using the application that it may make sense to publish the app in the market place.
Is this appropriate to do? Also, there are limits on each api key on how many requests can be done. Would a new api key get generated for each customer installing from the marketplace? Is there anything else I need to be concerned on this?
I didn't fully understand your questions so i'll try to answer the best I can.
Yes, it would be easier for your customers, especially new customers, to find your app in Marketplace. From there they can install it easier.
Not sure what you meant by "instead of going into the developer console for each customer currently using the application". Do you create a new console project for each customer?
Are you using the Provisioning API? This API is being deprecated and it will stop working by April 20, 2015. Instead you should use the Directory API.
What do you mean with "API Key"? Is it Project ID? When users install the app, the app will use the same Project ID. You should keep in mind that there are quotas for using Google services that will go against that Project ID.