Q:

Any tool to migrate repo from Vault to Subversion?

Are there any tools to facilitate a migration from Sourcegear's Vault to Subversion?
I'd really prefer an existing tool or project (I'll buy!).
Requirements:

One-time migration only
Full history with comments

Optional:

Some support for labels/branches/tags
Relatively speedy. It can take hours but not days.
Cost if available

Bonus points if you can share personal experience related to this process.

One of the reasons I'd like to do this is because we have lots of projects spread between Vault and Subversion (we're finally away from sourcesafe). It'd be helpful in some situations to be able to consolidate a particular customer's repos to SVN.
Additionally, SVN is better supported among third party tools. For example, Hudson and Redmine.
Again, though: we're not abandoning vault altogether.

A:

We are thinking about migrating from vault to git. I wrote vault2git converter that takes care of history and removes vault bindings from *.sln, *.csproj files.
Once you have git repo, there is git2svn.
I know it sounds like going rounds, but it might be faster than writing vault2svn from scratch.

A:

If you want full version history, you may want to just write a script that checks out each version from vault and checks it in with the comments to Subversion.
https://www.mercurial-scm.org/wiki/GenericConversion is a good example
Based on the documentation that I saw on the Vault website, look into the command line GETVERSION.
Use your favorite scripting language...
Implement the following process:

Check out a version from vault.
Get the commit comments for the changeset.
Add/remove the files to the SVN repo
Commit files using the commit comments
Go back to step one with the next version

