I havnt used that one, but I have a slide scanner. An old one.
After considering the same, as I too have an entire drawer full of old negs and slides from my photography days, I concluded that paying a photo shop to do all the scanning for me was a much better idea!
I also have a pile of 4x5 negs, those I have been scanning myself with a high resolution flatbed neg scanner. Painfully slow process, mainly due to the required cleanliness.
That one you linked to, I didnt look too hard, but does it require to to dismount the slide from the holder to make the scan?
Not all scanners require this. Something to think about, as dismounting every single slide in order to scan is a LOT more labor, as well as adding handling that may damage the slide itself.