Third Party Scanning Software/drivers

While looking for reviews of new Scanners I came across http://www.silverfast.com/product/en.html ,they provide third party software for numerous scanners.I tried the demo for my Umax 610s ,but it locks my system.Actually they don't have drivers for my 610s ,but I currently use MagicScan for the Powerlook II so I tried that one.Anyway ,has anyone ever tried SILVERFAST.Its seems kind of expensive ,but if you do alot of scanning ,it might be worth it?

Any Experiences appreciated,as before this I was unawarethat 3rd party software/drivers existed ,are there any others .

WG34