I think it was more that it was the first quality 2x15 I had. It was a bit underpowered and so I changed the speakers in it. Originally, I had a 1x18 cab and 2 4x12s (a smaller version of John Deacons rig) but it didn't sound right and was a mountain of stuff to cart around.
After the Ampeg 2x15 I bought a Boogie diesel 2x15 (well, two in fact) and have been a rampant Boogie user ever since then (about 1988).