I have two routers for various reasons.

  *  P660HW T1  This has excellent ADSL performance on my long phone line. Its main defect is that it periodically goes to sleep for roughly 3 minutes, stopping all network connections resulting in failed downloads, web page loading failures, etc.

  *  DG834G v5. This is very stable except for one problem.  Every day between 1700 and 1900 hours it repeatedly retrains the ADSL link every couple of minutes, resulting in failed downloads, etc. I don't have a rational explanation as to why the fault is time related.
It could be a neighbour using a mobile phone causing interference to the phone line, but I really don't know.

If it were possible to combine the best features of these two models you would have a very fine product.