Ok, so I did some searching on the net after I was encountering this issue: whenever I export to .jpg from Aperture, I get a 72dpi file. No matter how I set my settings for export its the same. I found some other people having the same issue and this has reportedly been going on for at least a year's time now. The only "fix" is to strip the photo of meta data and then do an export - and that will allow a 300dpi export. Any of you guys having this problem as well? Apparently, Apple still has not fixed this problem. I can open up the same RAW file in LR and export with 300dpi with all meta data intact.