In NXT, we're currently unable to send the same email to multiple lists of constituents without sending the same email individually to different lists. For example, I send a newsletter to all alumni, but want it to go to specific staff members as well. I have to send the email twice, once to the alumni, and once to the staff list. OLX allows you to create email lists with queries which can be combined.
Would definitely like the ability to send to multiple NXT lists at one time. It is very time consuming to have to resend an email several times.