I want one..... Just so much money. Me and RobertB hunt a lot together. He has the flir M24 recon in 640 as he said. I've been using my dads flir ps24. Honestly if he can see it, I can see it. If I can see it he can see it. He can just see a little better detail. But that little detail sure makes me want a 640!
Now, with that being said. Ask yourself if its worth $4000 more than a ps24 to see it a little clearer. I can see getting the 640 for a clip on or a dedicated scope but really if you just want to spot heat then the ps24 or 32 will hook you up. I have had the ps32 and I used the ps32 right beside the ps24 and I seriously can't tell a difference in the 2 other than the 32 has a 2x digital magnification.
Good luck sir!