Let me add that by dated I mean that ( A ): It is discontinued and ( B ): The box is a pretty basic design where only the parts within it make it what it is. Reason ( A ) is something to think about in the near future in reference to parts. Parts are going to eventually get harder to find.... So yes, it is dated. I don't think the SRX 700 series is a major step above other similar options available now. Same price you can get a passive 800 series speaker. The newer 700 series PRX line is a pretty close contender to the SRX 700 stuff, both in output and quality of sound. You also don't have to buy an amp. So while yes, the SRX 700 series is very good by even today's standards, it is not punching above its weight and is expensive in comparison.
I say stick with what you have until its demand and value drops a little more. The 728's are still very much on the want list and the others in that line still have some desire. Most won't say no to it and who knows, maybe in a few more years there will be an even better less expensive option?