I've carried a Micra for a long time, and love it, but got a new P4 Squirt for Christmas. The P4 is definitely now my new EDC.
Nobody has yet mentioned the most significant new improvement -- that the Squirt now allows all tools to be accessed WITHOUT OPENING the entire device -- except of course if you want to use the pliers (or scissors, depending on the model). The tools are now easily accessed like a conventional multi-function knife (e.g., Victorinox).
I used to use the scissors a lot on my Micra when I could have used the knife blade, but it was too much trouble to go the extra step. Now, with the P4, the knife is only one step and gets used for everything I was using the scissors for previously. I prefer the addition of the pliers (P4) than have the redundant scissors (S4).
The construction and design quality of Leatherman products is outstanding. I wouldn't even consider one of the other similar products.
All Squirts I've seen are in the blister packs except those in "tactical" supply stores, which come in boxes -- and are more expensive (??).
I wonder about the durability of the new color finish on the Squirt. Is it going to get scratched up in my pocket with coins, keys, and Arc AAA/Photon II? Because it's a Leatherman, I'm expecting it to be perfect.