Yamaha RX-V750 vs 757 vs 659 for non HDMI

Looking over slightly older (pre HDMI) AVRs - these 3 Yamaha models from 2004-06 appear to be essentially identical. They all include:

About the same rated wattage
Component video upconversion
6 discrete digital audio inputs
DTS and Dolby ... (exc DTS HD and Dolby HD)
The 659 has an iPod dock port

Beyond what I can learn from the owner's manuals - are there any other differentiators I should be aware of? Or just let price be a major deciding factor?

Also how does this grouping compare to the quality and performance of previous or current 'generations' of Yamaha receivers? (beyond obvious feature differences)

thanks

OK thanks. This range of 2004-06 AVRs represents a buyer's sweet spot in used Yamaha receivers if non-HDMI is OK. This range of AVRs appear on paper to be nearly indistinguishable. Arguably the older ones might represent the best value on the 2nd hand market but even there the price differences are not all that great.

Considering my current Yamaha AVR is approaching 20 problem free years since purchased new (extremely expensive back in the day too!) - I'm hopeful that a slightly used Yamaha AVR will be similarly long lived.

I've looked at the current/recent AVRs and for the price I was hoping for many more HDMI inputs. I decided I'd be frustrated w/ too few HDMIs soon enough (my TV has enough for now) - figured either get a whole bunch of HDMI inputs or none at all (for now). The RxV1600/1500/ etc have LOTS of digital audio inputs - another sweet spot...

thanks