I sold my Nitty Gritty 1.5FS in favor of a VPI 16.5
The NG's advantage is it applies the fluid on the record for you with a simple push of a button, whereas the VPI is a manual process (squirt some fluid on, work it in with the supplied brush). I also find the VPI clamp a bit finicky, you really have to crank it tight or the vacuum action will stop the record from turning. The VPI does a much better job of vacuuming, all in all my records come out much cleaner with the VPI.
The NG's advantage is it applies the fluid on the record for you with a simple push of a button, whereas the VPI is a manual process (squirt some fluid on, work it in with the supplied brush). I also find the VPI clamp a bit finicky, you really have to crank it tight or the vacuum action will stop the record from turning. The VPI does a much better job of vacuuming, all in all my records come out much cleaner with the VPI.