I actually compared these two directly last week.
I had gone into the store to try out the new Fender Rumble 500 combo.
After putting it through its paces, I plugged into the Ampeg setup.
Costs more, but still looks good, and until now has been one of my favourite sounding amps.
I'm gonna be straight up and honest....I preferred the Fender in every way.
Weight, tone, portability, looks etc.
Fender just really got it right this time around.
500 watts in a 16kg combo and it sounds great.
And I've never ever preferred a Fender to Ampeg before now.
FWIW...I personally feel that proper judgement of gear requires that it be heard within the context of a mix with a live band. I learned long ago not to think that 'music store sound' is the same thing.
I'm not saying you wouldn't prefer the Rumble in that setting too, but, I have heard both in the context of a live mix with lots of different players and lots of different types of bases and personally feel very different.