Which Leek?

After trying many different types including the 'blues' and Bulgarian varients I always come back to Mussselburgh which are hardy and I think a strongly flavoured leek? The comparative shortness of the white section isn't a problem for me as I use a goodly ammount of the green leaf part when I cook them.
I also grow a show variety of leek from leek 'grass' each year, purely because I can and these would be planted at this time of year. The problem with this, as with any cloning, (which is basically what I am doing) is that regression sets in and the yeilds deplete as the years go on!  The showmen counteract this by growing the same strain from seed every few years.