You cannot necessarily compare the delivery characteristics of a vISP with a true one. On any internet connection. Mobile or landline.
It depends entirely on what the contract between them is.
Seems like you were right about this at least in my case. I have got hold of a three sim and get significantly less packet loss compared to the smarty one, in fact it looks even better than my vodafone connection so I think I will be moving my contract to three as they are cheaper and speeds are better than on voda.
Thanks for the advice