[dba-SQLServer] Random autonumber ID

Hi all

I'm working on upsizing an Access backend to SQL Server and used Access' wizard for this.
That worked with no errors.

However, the client used Random Autonumber for IDs in Access and these are converted to integer with an associated trigger to create the random ID for new records:

USE [PPT]
GO
/****** Object:  Trigger [dbo].[T_UserLastDataTable_ITrig]    Script Date: 06/08/2012 16:19:49 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER TRIGGER [dbo].[T_UserLastDataTable_ITrig] ON [dbo].[UserLastDataTable] 
FOR INSERT 
AS
SET NOCOUNT ON
DECLARE @randc int, @newc int    
/* EMULATION CODE FOR AUTONUMBERING */
/* * EMULATION CODE FOR RANDOM AUTONUMBERING FOR FIELD "ID" */
SELECT @randc = (SELECT convert(int, rand() * power(2, 30)))
SELECT @newc = (SELECT ID FROM inserted) 

UPDATE UserLastDataTable SET ID = @randc WHERE ID = @newc


Is this really the best method?
Any disadvantages?
Would we be better off changing ID in Access to either sequential IDs or even GUID before running the update wizard?

/gustav