Is it possible to download (to Excel or other) the list of all users?

I've used the Host > SQL Tool and I've used the Reports module.

Here's a couple variations of a sample script:
DECLARE @PortalID int;
DECLARE @authorized bit;
SET @PortalID = 0
SET @authorized = 1
SELECT U.UserID
, (SELECT PropertyValue FROM UserProfile WHERE UserId = U.UserId AND PropertyDefinitionID = (SELECT PropertyDefinitionID FROM ProfilePropertyDefinition WHERE PropertyName = 'CustomPropertyName1' AND PortalID = @PortalID)) AS MyCustomProperty1 -- Used to get a profile field
, (SELECT PropertyValue FROM UserProfile WHERE UserId = U.UserId AND PropertyDefinitionID = (SELECT PropertyDefinitionID FROM ProfilePropertyDefinition WHERE PropertyName = 'CustomPropertyName2' AND PortalID = @PortalID)) AS MyCustomProperty2 -- Used to get a profile field
, (SELECT PropertyValue FROM UserProfile WHERE UserId = U.UserId AND PropertyDefinitionID = (SELECT PropertyDefinitionID FROM ProfilePropertyDefinition WHERE PropertyName = 'CustomPropertyName3' AND PortalID = @PortalID)) AS MyCustomProperty3 -- Used to get a profile field
, U.Username
, U.FirstName
, U.LastName
, U.Email
, U.DisplayName
, UP.CreatedDate
, UP.Authorised AS Authorzied
FROM USERS AS U
LEFT JOIN UserPortals AS UP
ON (U.UserId = UP.UserId)
WHERE ( UP.PortalId = @PortalId OR @PortalId IS NULL )
AND Authorised = COALESCE(@authorized, Authorised)
ORDER BY U.FirstName + ' ' + U.LastName

------------------------------------------------------------------

SELECT  
-- u.UserID
u.FirstName + ' ' + u.LastName AS FullName
-- , u.LastName
, u.Email
, u.DisplayName
, pr.PropertyValue AS MyCustomProperty1
, prn.PropertyValue AS MyCustomProperty2
FROM [Users] AS u
JOIN UserPortals AS up
ON (u.UserID = up.UserID
AND up.PortalID = 1
AND up.IsDeleted = 0
AND Authorised = 1)
JOIN UserProfile AS pr -- Used to get a profile field
ON (u.UserID = pr.UserID
AND pr.PropertyDefinitionID = ##somenumber##) 
JOIN UserProfile AS prn
ON (u.UserID = prn.UserID
AND prn.PropertyDefinitionID = ##somenumber##)

Hope this helps.