While Mark is watching a movie that I decided I have no interest in seeing the end of, I've been playing around on Ravelry.
One of the things that happens and I think is funny, is that the same threads get started on practically every knitting board. I used to look through the Knitter's Review message boards a lot and I've visited some others from time to time, and it was no surprise to me to see a discussion thread on Ravelry about "overrated yarns."
Now most knitters are going to have yarns they like and yarns they dislike and there are going to be various reasons for that. I'm not sure just personally disliking a yarn makes it "overrated" though.
I noticed a lot of comments that were down on yarn because they weren't soft. I think it is kind of silly to expect all yarns to be soft. Some people have pointed it out already, but you really have to match the yarn to the project. Would I knit a sweater I wanted to wear next to my skin with Lopi, Noro Kuryeon, Manos, or Lamb's Pride? Not likely- the mohair content in Lamb's Pride would certainly make me itch and the other 3 are not soft enough wools for my taste. Lopi is especially meant for outerwear. I made mittens with Lopi and while they are not soft, they are fine for their purpose. All along I figured that if they were too itchy for me I'd make a pair of liner pair of mittens out of Classic Elite Lush (I haven't felt the need so far). Lamb's Pride and Kuryeon are great for felting and Lamb's Pride can be beautiful for non-garments - like the Christmas Stockings I knit last year. I love Manos, but it is not evenly spun and it is a little scratchy. It is perfect for a scarf that is going to be worn over a jacket instead of next to skin. Once again, knowing that it has its irregularities, I wouldn't choose it for certain projects.
That said I think the complaint about the number of knots in Noro and some other yarns is legitimate. When you buy a skein of yarn that is meant to have these long color repeats, it really throws your project off when 2/3 the way through you run into a knot and the yarn attached is in the middle of a completely different color. I did not appreciate that when it happened to me and most other people don't either.
I think complaints about the way yarn holds dye or the way it wears are also legitimate. I think some yarns can be overrated for certain purposes too- for example, a yarn that may be hailed as a terrific sock yarn may make only mediocre socks but may be excellent for lace.
Everyone is entitled to their own opinion, and I guess my opinion is that it is unreasonable to expect all yarn to handle the way you envisioned it. Some yarn is going to have little pieces of straw or tiny burrs or whatever in it. You can usually tell this before you buy it, and if you know you don't have the patience for a yarn that rustic, then don't buy it, and certainly don't expect that you are going to get a soft cuddly sweater out of it. If you buy handpainted yarn, you have to be prepared that it might pool and it might stripe and might do any number of things you don't like. Sometimes you just have to play with it until you find what really shows off those colors in a way that is pleasing to you. I sort of feel like you need to understand that before you buy it, and if you don't have the patience, buy something else.
Oh, and if you are allergic to a certain fiber in a yarn, it is really unfair to say it is overrated and complain about the yarn as if it is its fault. Don't buy a yarn you are allergic to.