You cannot buy SWAT VTG new anymore (even though the website is still up)
If you find a second hand one it should be good but age may affect its reliability.
The VTG usually comes with adapters for 209 primers, 9mm rimmed and 12g blanks.
If you do find one I would advise to only use the 209 blanks because the 9mm can be dangerous for hearing and the 12g are outright banned at all sites.
I think the best option would be a Dynatex timed grenade which uses the 209's that are cheap and plenty loud enough.