Expensive fly lines. not anymore

I've bought quite a few expensive lines in the past few years. I must say that there are a few that I feel were of poor quality. Cortland 555 is probably the worst line i've ever purchased. After 3 weeks of fishing it about 3-4 days per week, it was cracked all over. The line stopped floating, and refused to shoot through my guides. Memory was a problem also. I bought the line in june. Even in the hot weather, the line wouldnt straighten.
 
There are a few lines that I am very fond of. They are as follows: (not in any particular order.
 
1. Cortland 444 (both DT & WF) - fishes well in cold conditions, and casts well. Never had much problem with the finish cracking.
 
2. Triangle taper - Best line ever, shoots well and lasts a long time, shoots through your guides like a rocket
 
3. SA "Trout" (WF) - great dryfly line, casts very delicatley, but doesnt turn over weight very well
 
4. Cortland 444 lazer line (DT) - loads rods nicely on short casts, great nymphing line
 
5. SA GPX (DT) - loads faster rods very well, fishes best in the warmer months, tends to coil in the winter

Some of the cracking you guys are seeing may be from sitting in the sun in the car or trunk or from being stringed and staying bend in the same spot on the guide. You also have to clean and treat the lines each yr at least once. The cracking sounds like heat problems and may not be line issues. I've only had one line crack on me and it was the heat of the truck and from being left stringed on the rod. At that time the line was more than a few yrs old.
Tom

Thanks for the input guys. The lines i have used in the past are orvis and rio. In Florida, I will still continue to use orvis wonderline. It works well in warm water, with no cracking prob. and I can tell the difference in casting distance. As well as rios striper line. For steelheading and trout. I am going to stick with the cheap line and see, really don't see the need for an expensive line. . My only concerns with the si angler cheap line is how well it will float using drys. Will let you know.
 
Thnx
Al

Airflo has (had) a lifetime guarantee on cracking for their polyfuse lines.  I have them in 5, 7, and 8 wt and they are great lines until they get in really hot weather.  I have the polyfuse 7000 series and when it hits 90 degrees they get a little soft and sticky.  Anything cooler than 80 and they are fine, all the way down to sub freezing.  They aren't PVC like standard fly lines, so they behave entirely different.

Thanks,
Rick