Dear Ruthierhyme
Do you mean the ones that you can adjust the angle or fixed?
If it's one that you can adjust the angle to suit you then i would say i have worked with these myself for crafting, and are okay as long as you adjust it properly. The static ones can be uncomfortable because you have to be a certain height for it to be comfortable otherwise you end up with a very sore back!!!
I tend to do all my work, whether it's crafting,typing or puzzles at an angle and i prefer it, but it's personal taste which is why the adjustable ones are much easier.
Hope this is of help
Portchesterqueen