I want to make some observations... PX-740A has only 33MB/s maximum bandwidth on IDE (UDMA-2), while PX-716A has up to 66MB/s max bandwidth on IDE (UDMA-4). Does this make a difference? At 16x DVD, the max Read/Write speed is 22.16MB/s, so that uses about 33% of the 716's bandwith vs. 66% of the 740's bandwidth.
The 716 just seems better in that comparison, but it would be nice to compare the data rates of the two side by side in sustained READING to see if capacity makes the difference.
Also, when I read the specs for PX-716SA (SATA), it has support for only 4x DVD+R DL, and the max bandwidth was 66MB/s (UDMA-4). That doesn't make sense to me. The SATA bandwidth should be 150MB/s shouldn't it? Obviously, SATA is better than PATA in part becasue of the ease of plugging & unplugging when you have to get into the case. But the real advantage is supposed to be bandwidth, right?