You will have to meet with the PIP on a couple of occasions at least, so maybe geographical location would be a factor.
Also, the issue of up-front fees might also be a contributing factor.
As this is a fairly new process, there is not much feedback on PIPs, but most have clear guidelines to follow, and should not be in the habit of misleading you with potential positive outcomes, as if they fail, then there will not be a fee for them, barring any agreed initial fees for taking you on.
Hope this helps.