I've had two, one courtesy of the fine Navy dental corps and one by the VA. The one the Navy did was a big deal, as they were just learning how to do it and hurt like hell when they punched the implant into my sinus. Note! The workup x-rays showed that was a possibility, and all was well after that healed.
It was a bit exciting, though, to feel and hear a loud crack and have the whole mob of Bethesda dentists say "oops".
The most recent at the VA was the fastest and easiest surgery I've had. The whole process took a few months but went like clockwork.
What sort of tooth are they putting on the post? I understand (and can vouch for) the cemented on type is the best. If you bite any bullets or other hard item, the tooth/cement will (hopefully) fail before the implant.
As far as pain, not as bad a root canal. It's the gums that take the beating, but it does ache for a while.
Terminator Teeth!
matthew