Can be interesting to know and a good feedback for Curious Labs! 1. The lack of a progress bar (I mean one that really works) during loooong renders. Not just seeing an empty progress bar with the label "Adding Objects". You really can't tell if the program is doing anything and after 24 hours it can be hard to keep waiting and I usually hit the cancel button. 2. Close to the above mentioned "hate", is the lack of an estimated time for renders. If you have an estimated time, lets say of 30 hours, you can shut the monitor off and just use an other computer to do other things and take a look every now and then to see if the ET is going down. Specially because the "Adding Objects" process uses 100% (or very close to that) of the CPU.