Quite a few of those cheaper track frames hovering around the tracks in Oz. Lots of happy campers, but if you check the ebay feedback on a lot of them, there is quite a bit of dodgy welding. So they can be good, but they can also be bad. Just depends if you want the bother of getting a bad one and having to send it back if you can or living with the imperfections.
You could likely get a much better second hand frame if you were prepared to sit and wait and scour the market.