hmmm... That is a tough question.
I really don't think there is a ton of difference, other than the UPCI is a much larger organization.
Some will say the WPF is more conservative in regards to dress standards, television, etc.. However, I've seen conservative and "liberal" churches in both organizations.
As far as ordination process. Last I knew, the UPCI has a very rigid process where you apply with the blessing of your pastor. You then go before a district board and answer questions about anything from doctrinal issues to your personal life and/or marriage.
So far, the WPF does not "ordain" ministers. However, you can apply for ministerial membership again with the blessing of your Pastor and $60
GIB stands for good independent brother... so that should speak for itself