I have both of what you are asking about. I would go with the 809, it features totally ambidextrous controls, changeable backstraps, field strip procedure is similar to Glock, and I happen to like hammer fired handguns. Plus, they still manufacture the 809. The 24/7 series is discontinued. I found the 809 slightly more accurate out of the box.
Taurus 24/7 Pro DS 9mm & .40;(2)Taurus OSS DS 9mm;Taurus OSS DS .40;Taurus 809;809 compact;840;PT709 "slim" SS;PT738;full size BUL Cherokee;SCCY CPX-2;Smith&Wesson BG .380;Arcus 98 DA;EAA witness P 9mm;I.O. inc. AK-47C;Zastava PAP;Mossberg 500 tactical;Marlin model 60.