Get Fast Rowcount

I came up with this little gem a while ago, I use it when I'm trying to get a rowcount on a large table, where it's so large that it takes a long time for a simple SELECT COUNT(1) FROM xxx to return data.

DECLARE @TableName sysname
SET @TableName = 'TableName'

SELECT SUM(row_count) AS [RowCount]
FROM sys.dm_db_partition_stats
WHERE object_id=OBJECT_ID(@TableName)   
AND (index_id=0 or index_id=1);