My line is around 1100m. On ADSL1 and ADSL2 (where the line length was 5+km) the 8800 performed, overall, the best of all the very many combos I've tried. Easily the best stability and error-coping - I never observed any sign of bit-loading decay. It wasn't quite the fastest, being only slightly exceeded by DG834GT with DGTeam firmware, but within a few days the DG834 would have suffered bit-loading decay and its max attainable rate dropped below the 8800's. Its wifi isn't outstanding, but was adequate if I ever needed to use it.
On VDSL2, it has been the best of around 5 tested. Highest sync rate, equal best stability and error rates (with ZTE H168N), no bit-loading decay, and I actually found some bit-loading growth a few times. Works well with DSLstats. I've tried all the issued firmwares, but have stuck with the original 2.32d.dm2
I'm on the Plusnet 40M package and get a max achievable of around 45000 and a bearer rate of around 39000 with interleaving at 754.......the interleaving has eliminated the periodic very high CRC rates - most probably electric-fence-affected - that I used to experience with ADSL and days 1&2 of VDSL.....5 stars for VDSL DLM!
Reading about other folk's experiences with other more expensive combos, but not having ventured into the higher-cost arena myself, the 8800NL would seem to be very hard to beat...I thoroughly recommend giving it a try. I don't know about other lines, but on mine, and with my simple requirements of best speed, good error handling, stability and consistency, it would seem the tops! I've not explored its wealth of other features, having no need at present.
Very highly recommended!!!