I had a blast flying as a charter pilot in the US. I have done both pax and cargo charters. It is interesting because you are going different places rather that a set-route. Sometimes, it is very demanding because of weather mins, duty times, etc. I am usually on call 5 days a week 24hrs a day.
Sometimes, we help out other companies too, e.g. when they have a plane down. We usually cover for them on a UPS/DHL run. I enjoy the work because it is varied. Sometimes you will find yourself landing at a big international airport and sometimes in a little airport out of no where.
The other interesting part is talking to other pilots hanging around, building your own contacts for future jobs, etc. I have never flown in Europe, so it will be interesting to hear from someone else over there sharing their views.