My department has 3 PI's. Here is the low down after we have been driving them for about 6 months.
#1 complaint.....not enough room and it is a b*tch to get out of the driver's seat. Front passenger seat is a joke. Now this could be because of the way the partition is set up, but, the way our is, it's impossible for anyone in full duty gear to sit in the passenger seat.
#2 complaint.....hard to see out of the back window
#3 complaint....not enough room for prisoners
#1 compliment....it's fast as hell
#2 compliment....it looks good.
So, our next round of orders, we are going to buy a few of the UTV (Explorer). We are going to go with the AWD 3.7 non EB. Not my first choice, but the cost was a little too much. The 3.7 is over 300HP so, it should do ok. AWD is much more important living in the NW. Roads are always wet.
Many of the agencies in the Seattle/Tacoma area are going to the UTV. Seattle PD just ordered 60.
I've got a 2010 SHO as my POV. I've driver our department PI a few times. In gear at work, it is a pain to get out of the driver's seat. I keep getting my radio and other equipment caught on the door pillar when hopping out. My regular patrol vehicle is a Tahoe for the moment. Lots of room, but under powered.