Well here's my review of the primo pro brake lever also sometimes known as the J lever.

To start with here is a little picture of it:

This is the only brake lever i have ever had to buy and i got it as a nice replacement for the stock tektro lever which came with my bike.
Some of the main features which made this stand out to me are the clamp design meaning you do not have to remove the grips to install and remove it and the shape of  the lever.
The price of this lever seemed to vary from shop to shop but it was still a few pounds (or dollars) more than a dirty harry or a tech 77.
The lever itself has a nice pre bent shape to it which means that even when run on the bend of the bar it still sits in a nice comfortable position to grab and pull.
The action of the lever is also very nice and smooth, it gives a lot of leverage and i definately noticed an increase in braking power with this.

Some things which i think could be improved on this lever are that it will not work with dual upper cables because of the large barrel adjuster. The only way to make them fit is to do some modding of your own.
I also recently found that the clamp is really hard to tighten on the bend of the bar, it seems like the angle that the back piece folds over at doesn't line up properly when it is on the bend and the screw is really hard to tighten in. Lastly i have heard of at least one person snapping this lever. I don't think i could snap it with the kind of riding that i like to do but if your a very hard rider who bails or does huge gaps/drops a lot then that could be something to think about.

So then to summarise:

Pros
+ oversized strong hardware
+ tough black finish
+ bolt already had loctite on!!
+ came with primo sticker

Cons
- slightly higher cost than competitors,
- hinge can be a bitch sometimes,
- cannot run dual upper cables.

I would give this a 7/10

Cost: about $20 USD