There has been a lot written about the 444 Sylk's on the Classic Fly Rod Forum at http://p205.ezboard.com/Fishing-Bamb...gbambooflyrods, just follow the link and do a SEARCH.
I've been fishing various wt's for three years now, and have had no complaints. The line is smaller in diameter than standard fly lines which makes them ideal on some of my older rods with small guides. They are very supple and fish well in cold weather, although I've heard that they become sticky in very warm conditions; I haven't experienced that problem. Tip sink has been noted as a problem, and I have experienced that, however I'm not sure that the problem is all the lines fault. Because the tip section is so light, I think that the mono and floro leaders are causing the tip to sink. I just dress the butt section of my leaders, and don't seem to have a problem.
The tip section on the DT lines is longer than on a conventional DT line, and I have found that I can improve the turnover of the leader/tippet by cutting the tip section back a bit.
Dan S
"I still don't know why I fish or why other men fish, except that we like it and it makes us think and feel." Roderick Haig-Brown, A River Never Sleeps