One of the attributes of the product that you purchase from an ISP is the details of the routing that it takes to get to destinations. This routing affects the latency to different destinations greatly.
Unfortunately, my requests to have ICASA include routing attributes as part of a products details in the ADSL regulations went completely ignored.
The only way forward now is to purchase each and every available unshaped product, and test them until you find the best one for your particular requirement.
Then, once you're happy and set, the ISP will change their providers and wham, the product that was working perfectly for 3 months will now be useless.
It's painful. And the lack of visibility regarding what you're actually purchasing is blatantly criminal.