I love the Gleason guide! I’ve never used the sidekick so I can’t compare. I bought the Gleason guide years ago and use it all the time. If anyone other than you sharpens your instruments it would be a smart investment
Both will work great. I use the Perio Star 3000 when I have time. I own the Gleason guide and found that gripping the instruments made my wrists and hands hurt if I had a lot of instruments to sharpen….love the Gleason though for small jobs.