Haha, I can't stop thinking how great it would be if I could get the PK3 to work.
So I tried, and got it to work. Here's the breakdown.
Opening IPE on my Windows computer:
At 24 seconds, the window finally opens, first indication that you have.
At 45 seconds, the output window says "finished loading IPE software"
edit: after several software reboots AND multiple plugging in/out of the programmer, I could finally get IPE to detect the programmer. And after it detects, it needs to "connect." This is 45 additional seconds to connect to the PK3, after you hit the "connect" button. And sometimes this fails, which takes 45 seconds to 60 seconds before the connect button lights up and can be tried, again. Note, this is NOT the download of new device firmware. I already have the appropriate device family firmware installed for the selected device.
So I might have had a failure to connect, before. I didn't wait for the connection message in the output window... I may have been "spoiled" by my PK2's that always connect in bout 1 second. Anyways, got a hex loaded in P2G mode. Took quite a long time to load into the device.
I used my genuine PK3. Flashing 27 PCB's, I had to reboot the thing a bout 6 times due to hangs. And it takes about 6-7 seconds to reboot. It is definitely faster than the PK2, but not by orders of magnitude. Something like 20% or 30% faster in this particular case. When I read back the devices on the PK2, they all verified, which has not ALWAYS been the case. Had one failure, before, with the genuine PK3, despite the programmer giving the thumbs up. The "W" clone is actually faster than the PK2. The genuine, with the hangups/reboots is about a break-even, at best.
*edit:
I may have figured out how to connect it. But with the length of time, I'm not sure if it's 100%.
Let IPE finish loading, full 45 seconds, before plugging the PK3.
After the PK3 enumerates, go and do something else for approximately 50 seconds. This is when IPE detects the programmer. Now, hit connect and wait another 45 seconds. And after you unplug the programmer, even if you use the "disconnect" button, don't expect to reconnect it, or any other PK3, without first closing and restarting the whole process from the beginning.

Win 7, 64 bit. 2.9Ghz i5 processor. Not that shabby. I'm pretty sure IPE hates Window 7, in particular. There are a lot of complaints with Win7 in particular.
Per my old notes, IPE is the only way I could get the PK3 to actually work in P2G mode. With an older firmware, I could do it in MPLAB 9, but it didn't work. With the latest firmware, it can only be done in IPE. If there's a way to do it in the standalone bugfest, I didn't figure it out.