I have an SVT-3 pro that I bought used for $700 and a SVT 410HE that I bought for about $650 new. So id say $700 for a more expensive cab and the same head is a great deal. But if your willing to pass up on the deal and get a combo amp that will still sound nice and save you a couple hundered...
Just out of curiosity was the horn knob on the back of the ampeg cab turned up? You can get a lot of trebble out of that. But then again I don't know what your taste is like its just something to try. Good luck on your search!
My first bass was a dean playmate, and the quality is almost as bad as you describe. I'm not sure how much the one you played cost, but mine was less than $200, so I always figured it was just the fact that its an entry level bass.