One button or two?

Question

I've got a web app where users can create two different kinds of similar things and I'm trying to decide whether to have two buttons, or one button and then present a choice as part of the resulting form. E.g.:

 [Create Primary Ownership] [Create Secondary Ownership]

vs.

[Create Ownership]   ->    (x) Primary    ( ) Secondary

I like the second one better even though it requires an extra click -- it's more scalable and less cluttered. The situation is more complex, though, because in one version of our product (for a particular set of users), the objects being created are labeled as above, but for a second set of users, the labels reflect the underlying structure better:

[Create Team]  [Grant Secondary Access]

vs.

[Create Team / Grant Access]    ->   (x) Team    ( ) Secondary Access

I hate the slash in "Create Team / Grant Access".

Answer 1

Two buttons

Two different operations. "Cluttered" is subjective. Best to do a paper test with a few users of course, but based on the information given I would find the second option confusing, while choosing one of two buttons seems obvious.

As a developer, I'm suspicious of anything labeled 'primary' and 'secondary', because 'tertiary' et al is implied ;)

Answer 2

In General
Jakob Nielsen touts the benefits of progressive disclosure. I think this, in principal, is a question of whether or not this is 1) a primary or secondary feature, and 2) if power or simplicity is what's most needed on this page. If you want to grant more power, use separate buttons; if you want to keep it simpler, use a single button with a second step.

Use Ellipsis
If you choose to break this into two steps, be sure to add an ellipsis to the end of your button text:

^{download bmml source – Wireframes created with Balsamiq Mockups}

Specifics
In the example you provide, it sounds like users are able to either start a group of people with access, or grant access to an existing group. It seems strange that you would go from an overview screen to grant access to a specific thing. Instead, I would follow the model you find on sites like Basecamp, or Google Docs: 1) from the index you can create a new thing, 2) from the specific thing you can edit access or other features.

In short: only have a Create Team… button, and on the Team page, have a Grant Access… button.