Hitec 545 is a 5-pole ferrite motor and so is a better servo. I think Futaba came out with the 3-pole ferrite high torque S3010 to compete with the Hitec 605. Don't know about S3310, but I do have a couple of S3305MG that are very strong, likely introduced to compete with Hitec's 615MG. All are good servos. I personally don't pay too much attention to all the hoopla about Hitec servos. I believe in using the right tool for thr right job. Some of these guys use Hitec's inexpensive 3-pole ferrite high torque standard servos (605, 615, etc) on 1/4 scale or larger 3D aerobats - and they wonder why they had problems.

Don't know about Worldtex. I'm sure it'll look more scale than ultracote, but I'm not much of a scale buff.