To me they are a notch above the 300 series in quality. I didn't buy any till I found out they were going to be discontined. I now have 4 different models and they are really great knives.
To me I think the price of the knife may of hurt sales. I remember in 99 seeing the large stockman 700 for about $55 while the large stockman 300 was $28. To me it was worth the difference, but lets face it $55 is still a chunk of change for the average buyer.
They did make quite a few 700's and it was out for years, collectable yes, but I would think the price would not rise too much due to the numbers made. I am sorry the stopped making them. To me the 700 and 500 series are my favorites.