(short version)
A good article about torque wrenches would at least start by a description of the different main types and their specific use.
http://www.doityourself.com/stry/6-type ... -explained (for your bike you want a click-type)
I knew a guy that ruined some things on his bike after buying and using a torque tool because he was waiting on the click that never came (he had bought a deflecting type, lol)
A torque wrench is a precise instrument that need to be handled with care.
Besides the shape, easiness of use, easiness of reading out, size, bulkiness, no sharp edges, reversibility, etc etc (there are many parameters you can bring in) you want definitely a tool that can be trusted in a way that it will perform equally for a long period of time. Therefore skip the ultra cheap ones. A budget tool is also not worth calibrating. Because most calibrating services are not exactly cheap.
As mentioned a torque wrench is performing best somewhere in the mid range of the tool capacity.
For your bike a tool that works within 2-25 Nm is a good standard recommendation.
Fixed Nm tools I would not recommend. Better buy an adjustable one.
You don’t need a bike brand tool. On the contrary there are many respectable tool brands way better than those bikebrands. Often they have their own service channels for calibration too.
I have 2 Gedore torque wrenches. Got them with a special offer from Gedore. (just as many other brands they have seasonal/annual offers for promotion) Still on the price but way cheaper than normal. And there is my recommendation: While this is an international forum, look in your location for special offers. Prices for exactly the same tool can vary dramatically.
The bikeradar topic only shows a handful tools, there are many more others. Also it is just a collection based on what manufacturers probably have sent to them to test. Makes it a limited test where you can’t do much with. Where are the real big names in tool land?
Bike specific: I miss the Syntace torque tool (formaly they had a calibration service of 25 euro, dunno if it still exist)
A-brands normal wrench type: Just fill in yourself
A-brands with T-handle or pistol like grip are also interesting for bike mechanics: Wiha, Pb Swiss Tools, CDI, etc
Then you also have to know how to use a torque wrench proper.
Most times given Nm is the torque for the bolt and is max torque.
Lubrication has effect on torque. (Lubrication factor)
You can bring in parameters as the material of the bolt, threads, specific lubes to calculate the right Nm. All these things have their own influence. In other industries this is known but not common in the mediocre bike industry. They seldom or never give you right instructions with the right Nm.
So just have in mind : With lube you always should lower the torque. And you always lower Nm in a way you stay on the safe side. A torque wrench for bike purposes doesn’t prevent you from disasters but makes you can work with a specific controlled amount of Nm all the time.
Never use your torque wrench as a normal wrench.
Store the torque wrench in a safe place, so not in your toolbox but in a closet.
Set it back to zero Nm when stored.