Using TRY / CATCH to perform INSERT / UPDATE

I have this pattern in a number of stored procedures

-- Table1
[id] [int] IDENTITY(1,1) NOT NULL
[data] [varchar](512) NULL
[count] INT NULL

-- 'data' is unique, with a unique index on 'data' in 'Table1'
BEGIN TRY 
    INSERT INTO Table1 (data, count) SELECT @data,1;
END TRY
BEGIN CATCH
    UPDATE Table1 SET count = count + 1 WHERE data = @data;
END CATCH

I've been slammed before for using this pattern

You should never have exception "catching" in your normal logic flow. (Thus why it is called an "exception"..it should be exceptional (rare). Put a exists check around your INSERT. "if not exists (select null from Data where data = @data) begin /* insert here */ END

However, I can't see a way around it in this instance. Consider the following alternative approaches.

INSERT INTO Table1 (data,count) 
SELECT @data,1 WHERE NOT EXISTS 
    (SELECT 1 FROM Table1 WHERE data = @data)

If I do this, it means every insert is unique, but I can't 'catch' an update condition.

DECLARE @id INT;  
SET @id = (SELECT id FROM Table1 WHERE data = @data)

IF(@id IS NULL)
    INSERT INTO Table1 (data, count) SELECT @data,1;
ELSE 
    UPDATE Table1 SET count = count + 1 WHERE data = @data;

If I do this, I have a race condition between the check and the insert, so I could have duplicates inserted.

BEGIN TRANSACTION
   DECLARE @id INT;  
   SET @id = (SELECT id FROM Table1 WHERE data = @data)

   IF(@id IS NULL)
       INSERT INTO Table1 (data, count) SELECT @data,1;
   ELSE 
       UPDATE Table1 SET count = count + 1 WHERE data = @data;
END TRANSACTION

If I wrap this in a TRANSACTION it adds more overhead. I know TRY/CATCH also brings overhead but I think TRANSACTION adds more - anyone know?.

People keep telling me that using TRY/CATCH in normal app logic is BAD, but won't tell me why

Note: I'm running SQL Server 2005 on at least one box, so I can't use MERGE

via Chebli Mohamed