In line strainers seem easier to use, but it is a myth
When we started building fence, we used the two different types of inline strainers. The advantage these strainers have is that you do not have to cut the fence wire and insert the strainer. Despite this advantage, I would highly recommend avoiding these strainers. They are much harder to actually get onto to the fence and tightened then you might think. They do not tighten as easily as my recommended strainer style because they do not have a stop on them. You have to keep holding the stainer tight wile you inset the pin they come with or a piece of wire to prevent them from loosening, making them much harder to adjust. I have often found that these strainers are even expensive then the ones I prefer as well. The clunky nature of tightening these strainers means that you can not get them as tight as our preferred strainers and I have had considerable trouble keeping sheep in where these strainers have been used so come spring they will all be replaced (luckily there are only around a dozen of them).
I would highly recommend framed or box strainers
Since I started using these strainers, I have not looked back. I put in about 250 of these strainers this year.
To install them, you have to cut the wire and insert it through the loop end (left side of pictured strainer) and either put on a crimp-sleeve on it or learn to bend high tensile and tie it off (it will save you a crimp sleeve which are $13 cents each). Then you thread the wire through the spindle (right side of pictured strainer) bend it off and cut it so it does not catch. Lastly tighten the stainer to desired rigidity. The strainer tool (blue hand tool) is essential and inexpensive at less then $5. The best price I have found is from Premier One Supplies over in Washington, Iowa.
We also use the box strainer for holding our corner posts together
So when the weather breaks this spring and you find yourself out fencing, stick to the framed or box strainers and you will be much happier in the long run. I hope you enjoyed this review and stay tuned for more thoughts on products we use.