Leadtools is ridiculously fast, and I was using a version that was about 5 years old or so. I imagine newer releases are faster yet. You pay for the speed though. Last time I checked, their price for the document imaging toolkit was around $2000. If you're going to use this for other projects, I highly recommend it. Or, if your client has deep pockets and is willing to pay, then I'd recommend it too ;)

Hope this helps. Let me know if there's more I can do.

Cheers!
MrCromeDome