Before you even start looking for a workshop vacuum, you need to think about what are you going to use it for.
Workshop vacuums are excellent for cleaning your workplace, but they can also serve a myriad of other purposes.
Some come with the ability to suck up dangerous fumes and dust from tools. This type of vacuum is usually referred to as a dust extractor.
If you’re going to be dealing with liquids a lot, you should look for a wet and dry shop vac.
Lastly, some shop vacs feature a blower port you can attach the hose to and use the vacuum for blowing leaves or dust, and even blow up balloons and balls.