Another important consideration to make when looking for the best combo amp is gain. Gain is the amount of signal coming into your amplifier, and a different thing to an amp's volume.
Some amps, like the Fender Deluxe have loads of clean headroom, so they won’t break up until you really get the volume cranked. This makes them perfect for those wanting a clean sound at high volumes, or for those that want to shape their sound further via pedals. Some solid state amps like the Roland Jazz Chorus are known for their clean sound at any volume, again making them a great pedal platform.
Some amps have a dedicated gain knob that allows you to dial in overdrive to your liking. On some models, this will be subtle and you’ll get great crunchy tones, perfect for blues and classic rock. Others will have more gain on tap allowing you to delve further into the realms of hard rock and heavy metal. Most modeling amps allow you to cover all bases, with various different clean and distorted amp emulations built in, though the quality of tones might not be quite as good as the real thing.