I met a woman while playing at Resorts World that hand-made a similar product. She used to sell them, but said that eventually the time and effort wasn't worth what she would charge ($15), so she now only has her own, and will make some for friendly regulars.
Again, it wasn't exactly the same, but the concept is. It puts your beverage in front of you (no twisting for a side cart), puts it where you like it (left, right or center), and it sits lower than an in-rail or a slide-under, so taller drinks don't interfere with play.
I'd rate the concept good, but $200-$250 isn't worth it for an off the shelf table, and if you are going with a custom table, you can do better.