adapter for 35mm slides/film?

My grandfather passed away 2 weeks ago and we've come across over 1000 35mm slides... I'm looking for a good inexpensive way to transfer them to digital.

We've seen the crappy ION mini scanners, we've bought an HP flatbed scanner that will do them. Neither work very well. I've seen somewhere, someone used a lens attachment and used a camera to capture the images...

Does anyone have any info, experience, or any other method that works well?

You are way better off with a film scanner, not an attachment for your camera.

why is that? I am totally unencumbered by any experience on the subject, but faced with a similar purchase in the near future. I was thinking that a lens adapter would allow me to control the light source with filtration or by using "full spectrum" bulbs, where a scanner is gonna give me whatever it uses and make me batch process my color corrections to get to a decent startpoint.
scanner=cheaper, easier, consistant, versatile.
adapter= another lens in bag (50f2.5 for the flat field of focus and 52mm threads the bower wants to use) and adjustability for color correction via the old subtractive method.
less than two hundred for the canon 8800 scanner, 350 for the one trick pony adapter and lens

why is the scanner hands down better?