It would seem to be common knowledge that the PIAT was shit and the bazooka the dog nuts and the Panzerfaust the best thing since sliced bread.
As with most things it is never that simple.
Personally I think the PIAT was a good design if a bit over engineered and could have done with one of two lbs being removed from it but as A/T weapons go at 32lbs it was not that heavy (Carl Gustav was 36lb, which when you compare it to a GPMG plus ammo or a radio or a 2 inch and ammo it is all about the same.). Its limiting factor was that it had very little scope for up grades and life extensions. As a weapon it was very short and almost silent with no signature, a big thing when you are firing at short range as all A/t weapons of that time did. Another advantage was the range of ammo available for the PIAT so it had a wider use than just A/T.
The basic concept of the weapon was to provide a recoilless weapon (having fired a number of so called recoilless weapons, they may not push back but your nuts a squeezed and your insides feel it.). To some extent this was achieved by use of a FO big spring which had the job of reducing the recoil. Contrary to most articles written about the PIAT it was not the spring that launched the bomb but the charge in the base of the bomb which was activated by the spring going forward and striking the charge. The inside of the bomb was the barrel so to speak unlike most weapons which have the barrel on the outside. The resulting explosion would be countered by the spring and so not transmitted to the firer, hopefully.
You will read many articles which happily point out that cocking this spring was difficult and very hard under fire. As a competent soldier one would be expected to have done this as part of your battle prep and so alleviate the need to do it as the tank rumbled towards you. Another advantage the PIAT had was that the choice of ammo could be left to when the need arose unlike other weapons of this type. Loading was very quick and simple and could be done by one person.
I came across a comment by another poster on another site that said that the Canadian forces asked the infantry which weapons they found most useful during D-Day and the months after. Number one was PIAT. They also said that the PIAT had accounted for 6% of all tank kills in this time. I have no information to back p this claim and would very much like to see more of this.
Bazooka next.