Having used both crimp beads and tubes, I much prefer the tubes. They work much better and the finished crimp looks nicer to me. As for the crimps with the loop on the end, I have some of them that fit right over the end of my beading wire, and then you just flatten it down with regular pliers. I tend to use them for multi-strand pieces or illusion necklaces where a crimp tube just wouldn't look quite right. I only use them for lightweight pieces though. I don't think they'd hold up well with heavy beads. I know they come in different sizes depending on what size beading wire you're using.
The "crimp" tubes with the ring on one end are not actually for crimping but for glueing them to cord ends. They make a real nice finish but it's not easy to fiddle the cord inside the tube, as the tube shouldn't be too wide.
I use silk and knot when I string, so I can't really join the discussion about crimp tubes/beads, but I can offer my favorite finish tips for this type of work (I think I wrote this in a post several months ago, but it bears repeating).
1 - I always use bullion wire - it serves the same purpose as "wire guards" when using beading wire. It comes in gold color or silver color, in varying diameters, and a little goes a very long way.
2 - When I start a necklace, I actually begin by finishing one end completely. I string the first few beads of my pattern in reverse order on a single length, then a 2mm seamless silver or gold bead, then another identical bead in the same color, a 1/4 inch length of bullion wire, one side of the clasp, and finally another 2mm bead. You should leave yourself a very generous tail to work with (about 10 - 12 inches).
3 - I then pass my needle the first 2mm bead and pull until the bullion wire is wrapped around the clasp and the two other 2mm beads are resting on the first 2mm bead (the wire should form a "U" or horseshoe shape. I place my first knot here.
4 - I pass my needle through the other beads I've strung and knot according to the pattern.
5 - I then move my needle to the other side of the thread and double it, leaving a tail the same length as the one on the side I had just finished off. I then string a few more beads according to the pattern, and using a second needle on the tail of the side I just finished, pass through one or two of these beads and knot according to the pattern.
6 - After stringing the remainder of the necklace, and knotting between the beads (again, according to the pattern), I leave the last few beads unknotted, making sure that the holes on these beads are large enough that I can pass my needle, with thread, through the holes a second time.
7 - I use the same technique of three 2mm beads and bullion wire to add the other side of the clasp, and place a half hitch knot between the beads according to the pattern. I try to end by passing the thread through a large bead, pulling tight and cutting it of without placing a knot to that the tail end inside the large bead. I always put a drop of Hypo-Cement on the last knot on each side of the necklace before trimming off the excess thread.
Hope these hints help,
Please see my projects at Stoneheart Beads
Those are some great tips. I'm doing a project where I will be stringing and knotting (if the beads ever arrive!)
I have always used tubes. I like to be able to easily get a thumb nail between two beads before I finish a thread. There should be a little give too. I think I"m just picky. The last few I did I liked so maybe I'm finally getting the knack! lol