Haven't ridden the PE but I reckon the IT175F was a top bike. It was my first full sized bike would take you anywhere without complaint. It's not a rocketship but had nice usable power that you could just hold on everywhere. I reckon they were a bit restricted and with a bit of tuning it should really get up and go. If you took the core out of the silencer it was noticibly faster and felt more like a big grunty 125 motocrosser.
The mellow power was great for wheelying, here's a shot from near the house at Rockley, New Year's Eve afternoon 1980. In the days of army boots.... and hair!
A few hours after this shot we ran out of grog so decided to ride (too pissed to drive) to Rockley pub for more supplies. Two up on the IT175 with Ribbo on the back, pitch black, pinned in 6th, over a crest and into a mob of cattle.
At times like that you multiple thoughts all at once, stuff like ... thank God Yamahas have such good brakes... who the fork invented bendy plastic brake levers anyway... hereford bulls have really nice eyes up close... geez Ribbo's a heavy bastard. Well the razor sharp handling of the IT allowed us to scythe our way through the mob with only a slight nudge or two on the way through to continue the adventure.
Can't comment on the PE but have spent plenty of time on TS and ER 185s and would take the IT any day.