Pictures would help. As a generalization, in the past, if I recall correctly, Spoilers were selling for around $1,500. I have no idea what they are trading for now. The condition can be a factor in market value; but, again as a generalization of past observations, if it's in reasonably good shape, $1,500 would not be unreasonable. However, current market conditions are a bit slow, as is the economy in general.
The Spoiler should sound significantly different from the Epic. The Spoiler is a neck-through, while the Epic is a set-neck; so there is a difference in the frequency curve. The Spoiler will have a more even response curve, while the Epic while have that set-neck/bolt-on mid-range bump.
The Spoiler has a low-pass filter and a Q switch, where the Epic has bass and treble boost/cut controls. The tones that can come from a low pass filter circuit are significantly different from the tones that come from bass and treble boost/cut controls. And the 8db bump the Q switch provides at the low pass filter cut-off point adds another source of tones that the Epic doesn't have.
I believe the Spoiler probably has a brass bridge block under the bridge, while the Epic probably does not. Along with the neck-through construction, the bridge block helps add sustain.
Any differences in body woods will also result in differences in tone.
As to whether you are better off is for you to decide. Both are quality instruments and each has its own distinct voice.
When I sent my Essence to Santa Rosa for upgrades, I purchased a Spoiler which was my main bass for a while. I was quite pleased with it; it played great and it had a great tone.
