I've used the magic circle a few times, and really like it. However, I always have to look it up before using it! (It's like casting on in knitting- I've done it, can't remember how, have to re-learn each time) But it works like a champ when I've done amigrumis.
My tension is pretty tight-- in this most recent piece I'm working hard to have it looser. I hate having seams, so I usually work flat pieces. Not on the table though, that would be awkward for me!
How do y'all weave ends in? If it's where I'm changing color, I stitch right over it, or incorporate it into the stitches I'm making. The very last end I will messily have follow stitches, and then twist in to the existing crochet. It's ugly, but it seems to work. It's worked well enough that several blankets I've made which have been washed, are still in one piece.