If you're travelling around a lot, some people prefer a USB oscilloscope. But, if you're spending the majority of your time in the same place engineers almost universally prefer a stand-alone bench top scope.

Pros of USB oscilloscopes:
 - Smaller & more portable 
 - Sometimes cheaper 
 - Sometimes more integrated capabilities

Pros of Benchtop oscilloscopes:

 - Dedicated controls (knobs, buttons, ect.) + streamlined GUIs vastly improve usability
 - Often better specs - bandwidth, waveform update rate, max input voltage

This talked about in more detail in the "5 Common Mistakes People Make When Buying a Low-Cost Oscilloscope" here:

https://www.keysight.com/main/editorial.jspx?cc=US&lc=eng&ckey=2830640