I've played thro both cabs.
They both have their plus & minus points.
It all depends on what type of sound your looking for.
From my personal experiences with them live, i found the Ampeg to be very boomy & the engineers
& my guitarists were forever telling me to turn down the bass. So the sound lost its character.
With the Swr, the engineers would usually commend me on the sound & afford me more volume,as its bottom end wasn't so big & they could control the mix better.
The guitarist liked the sound better for the reason of that it was a lot cleaner
sounding & they could hear the actual notes i was playing & didn't muddy the onstage sound.
I personally also found the Swr to be a clearer sound onstage, it just cut through what everyone else was doing
alot better. It wasn't as bass heavy, but that depends on what amp you use.
I've tried them both with different amps, the Ampeg almost sounded the same didn't matter what amp i used, whereas
the Swr sounded different depending on what amp was used.
If at the time i could've afforded & had the space i would've gone for the Swr Senior.
As it is i own Goliath 2 x 10 juniors.
The best advice i could give is try before you buy, but with the amp you have, i personally would stick with the Senior.