In that case, John, I'd still consider the BK-7m. You ought to be able to find one of those used for about the same price as your S750 is worth. The bottom line, as some have already said from playing the BK series, is that Roland have done a MUCH better job at balancing and voicing the styles than they did on the G/E series.

That's not to say you can't get close on the E80 with work (especially with a couple of SRX cards in it... I'd recommend the SRX-07, as it has some exceptionally good basses and guitars along with a ton of usable keyboard sounds), but OOTB, the BK's seem set up better.

Don't forget (unless it comes with it) that any SRX cards you add to the E80 are probably going to set you back $100-200 (the SRX-07 seems to keep its value fairly high!) so factor that into your costs.

Not to mention, TBH, the E80 is a dead fish. No more updates, no new styles, WYSIWYG... The BK series is the base for all new Roland style development, and is still being updated and improved. You would be future proofing yourself a bit with that.

That being said... yes, it's a crying shame Roland dropped the Dynamic Arranger. They have an uncanny ability to find obscure but incredibly useful features and axing them. Sometimes I think they troll the forums, and if I like a feature, they go 'We got to get rid of THAT!'...